diff --git a/addons/purchase/purchase_view.xml b/addons/purchase/purchase_view.xml
index e8e8d62190d..47a199c7bd9 100644
--- a/addons/purchase/purchase_view.xml
+++ b/addons/purchase/purchase_view.xml
@@ -171,7 +171,7 @@
                     <button name="picking_ok" states="except_picking" string="Manually Corrected"/>
                     <button name="invoice_ok" states="except_invoice" string="Manually Corrected"/>
                     <button name="purchase_approve" states="confirmed" string="Approve Order" class="oe_highlight" groups="purchase.group_purchase_manager"/>
-                    <button name="wkf_send_rfq" states="confirmed, approved" string="Send PO by Email" type="object" context="{'send_rfq':False}"/>
+                    <button name="wkf_send_rfq" states="approved" string="Send PO by Email" type="object" context="{'send_rfq':False}"/>
                     <button name="view_picking" string="Receive Products" type="object" attrs="{'invisible': ['|', ('shipped','=',True), ('state','!=', 'approved')]}" class="oe_highlight"/>
                     <button name="view_invoice" string="Receive Invoice" type="object" attrs="{'invisible': ['|', ('invoice_method','=','picking'), '|', ('state','!=', 'approved'), ('invoiced','=',True) ]}" class="oe_highlight"/>
                     <button name="action_cancel_draft" states="cancel,sent,confirmed" string="Set to Draft" type="object" />
diff --git a/addons/purchase/res_config.py b/addons/purchase/res_config.py
index ae3a172ce3c..13f189664fd 100644
--- a/addons/purchase/res_config.py
+++ b/addons/purchase/res_config.py
@@ -54,6 +54,10 @@ Example: Product: this product is deprecated, do not purchase more than 5.
             help="""Purchase Requisitions are used when you want to request quotations from several suppliers for a given set of products.
             You can configure per product if you directly do a Request for Quotation
             to one supplier or if you want a purchase requisition to negotiate with several suppliers."""),
+        'group_advance_purchase_requisition': fields.boolean("Manage multiple bidding on purchase requisition",
+            implied_group='purchase.group_advance_bidding',
+            help="""In the process of a public bidding, You can analyse the bidding lines and choose for each product from 
+            where you want to buy it as well as the quantity"""),
         'module_purchase_analytic_plans': fields.boolean('Use multiple analytic accounts on purchase orders',
             help ="""Allows the user to maintain several analysis plans. These let you split lines on a purchase order between several accounts and analytic plans.
                 This installs the module purchase_analytic_plans."""),
diff --git a/addons/purchase/res_config_view.xml b/addons/purchase/res_config_view.xml
index 276dc892392..6983acb854a 100644
--- a/addons/purchase/res_config_view.xml
+++ b/addons/purchase/res_config_view.xml
@@ -66,6 +66,10 @@
                                 <field name="module_purchase_requisition" class="oe_inline"/>
                                 <label for="module_purchase_requisition"/>
                             </div>
+                            <div attrs="{'invisible': [('module_purchase_requisition', '=', False)]}">
+                                <field name="group_advance_purchase_requisition" class="oe_inline"/>
+                                <label for="group_advance_purchase_requisition"/>
+                            </div>
                             <div>
                                 <field name="module_purchase_analytic_plans" on_change="onchange_purchase_analytic_plans(module_purchase_analytic_plans, context)" class="oe_inline"/>
                                 <label for="module_purchase_analytic_plans"/>
diff --git a/addons/purchase/security/purchase_security.xml b/addons/purchase/security/purchase_security.xml
index 4e1cf8b6107..d8b2d320fb1 100644
--- a/addons/purchase/security/purchase_security.xml
+++ b/addons/purchase/security/purchase_security.xml
@@ -21,6 +21,11 @@
         <field name="implied_ids" eval="[(4, ref('analytic.group_analytic_accounting'))]"/>
     </record>
 
+    <record id="group_advance_bidding" model="res.groups">
+        <field name="name">Advance bidding process</field>
+        <field name="category_id" ref="base.module_category_hidden"/>
+    </record>
+
 </data>
 <data noupdate="1">
 
diff --git a/addons/purchase_requisition/purchase_requisition.py b/addons/purchase_requisition/purchase_requisition.py
index 7f2a740b9f0..e889f0dd411 100644
--- a/addons/purchase_requisition/purchase_requisition.py
+++ b/addons/purchase_requisition/purchase_requisition.py
@@ -57,7 +57,7 @@ class purchase_requisition(osv.osv):
         'po_line_ids': fields.function(_get_po_line, method=True, type='one2many', relation='purchase.order.line', string='Products by supplier'),
         'line_ids' : fields.one2many('purchase.requisition.line','requisition_id','Products to Purchase',states={'done': [('readonly', True)]}),
         'warehouse_id': fields.many2one('stock.warehouse', 'Warehouse'),        
-        'state': fields.selection([('draft','New'),('in_progress','Sent to Suppliers'),('open','Choose Lines'),('cancel','Cancelled'),('done','Purchase Done')],
+        'state': fields.selection([('draft','New'),('in_progress','Sent to Suppliers'),('open','Choose Lines'),('cancel','Cancelled'),('done','PO Created')],
             'Status', track_visibility='onchange', required=True)
     }
     _defaults = {
@@ -205,28 +205,38 @@ class purchase_requisition(osv.osv):
         """
         po = self.pool.get('purchase.order')
         poline = self.pool.get('purchase.order.line')
+        wf_service = netsvc.LocalService("workflow")
         id_per_supplier = {}
         tender = self.browse(cr, uid, id, context=context)[0]
+        if tender.state == 'done':
+            raise osv.except_osv(_('Warning!'), _('You have already generate the purchase order(s).'))
         for po_line in tender.po_line_ids:
-            if po_line.state == 'confirmed':
+            #only take into account confirmed line that does not belong to already confirmed purchase order
+            if po_line.state == 'confirmed' and po_line.order_id.state in ['draft', 'sent', 'bid', 'cancel']:
                 partner = po_line.partner_id.id
                 if id_per_supplier.get(partner):
                     id_per_supplier[partner].append(po_line.id)
                 else:
                     id_per_supplier[partner] = [po_line]
 
-        #TODO generate po based on supplier and check if a draft po is complete before creating a new one
+        #generate po based on supplier and cancel all previous RFQ
         for supplier, product_line in id_per_supplier.items():
-            #duplicate po_line and change product_qty if needed
-            line_ids = []
-            for line in product_line:
-                line_ids.append(poline.copy(cr, uid, line.id, default = {'product_qty': line.quantity_bid}, context=context))
             #copy a quotation for this supplier and change order_line then validate it
-            quotation_copy_id = po.search(cr, uid, [('requisition_id', '=', tender.id), ('partner_id', '=', supplier)], limit=1)
-            new_po = po.copy(cr, uid, quotation_copy_id, default = {'order_line': line_ids}, context=context)
+            quotation_id = po.search(cr, uid, [('requisition_id', '=', tender.id), ('partner_id', '=', supplier)], limit=1)[0]
+            new_po = po.copy(cr, uid, quotation_id, default = {'order_line': []}, context=context)
+            #duplicate po_line and change product_qty if needed and associate them to newly created PO
+            for line in product_line:
+                poline.copy(cr, uid, line.id, default = {'product_qty': line.quantity_bid, 'order_id': new_po}, context=context)
+                #set previous confirmed line to draft
+                poline.action_draft(cr, uid, line.id, context=context)
             #use workflow to set new PO state to confirm
-
-            #TODO set previous line to cancel
+            wf_service.trg_validate(uid, 'purchase.order', new_po, 'purchase_confirm', cr)
+            
+        #cancel other orders
+        for quotation in tender.purchase_ids:
+            if quotation.state in ['draft', 'sent', 'bid']:
+                wf_service.trg_validate(uid, 'purchase.order', quotation.id, 'purchase_cancel', cr)
+            
 
 class purchase_requisition_line(osv.osv):
 
@@ -302,6 +312,9 @@ class purchase_order_line(osv.osv):
                 self.write(cr, uid, ids, {'quantity_bid': element.product_qty}, context=context)
         return True
 
+    def generate_po(self, cr, uid, id, context=None):
+        print '-----------------------------------------'
+
 class product_product(osv.osv):
     _inherit = 'product.product'
 
diff --git a/addons/purchase_requisition/purchase_requisition_view.xml b/addons/purchase_requisition/purchase_requisition_view.xml
index 78e64fda6ae..9541f655c85 100644
--- a/addons/purchase_requisition/purchase_requisition_view.xml
+++ b/addons/purchase_requisition/purchase_requisition_view.xml
@@ -228,7 +228,7 @@
                     <field name="lead_time" />
                     <field name="state" invisible="1"/>
                     <field name="invoiced" invisible="1"/>
-                    <button name="action_draft" states="confirmed" type="object" string="Cancel Bid" icon="gtk-cancel"/>
+                    <button name="action_draft" states="confirmed" type="object" string="Cancel Choice" icon="gtk-cancel"/>
                     <button name="%(action_bid_line_qty)d" type="action" states="draft" string="Change Quantity" icon="gtk-ok"/>
                     <button name="action_confirm" states="draft" type="object" string="Confirm Order" icon="gtk-apply"/>
                 </tree>
diff --git a/addons/purchase_requisition/static/src/js/web_addons.js b/addons/purchase_requisition/static/src/js/web_addons.js
index 4624bf24520..01c6b68553f 100644
--- a/addons/purchase_requisition/static/src/js/web_addons.js
+++ b/addons/purchase_requisition/static/src/js/web_addons.js
@@ -22,9 +22,7 @@ openerp.purchase_requisition = function(instance) {
         },
         generate_purchase_order: function () {
             var self = this;
-            //self.dataset.model = current model (purchase or else)
             new instance.web.Model(self.dataset.model).call("generate_po",[""]);
-            //self.dataset.parent_view.recursive_reload();
         },
     });
 }
\ No newline at end of file