diff --git a/addons/purchase/purchase.py b/addons/purchase/purchase.py
index cfcaa5bbed5..b29daf19731 100644
--- a/addons/purchase/purchase.py
+++ b/addons/purchase/purchase.py
@@ -441,11 +441,9 @@ class purchase_order(osv.osv):
             'move_lines' : [],
         }
          
-    def _prepare_order_line_move(self, cr, uid, order_line, picking_id, *args):
-        loc_id = order_line.order_id.partner_id.property_stock_supplier.id
-        dest = order_line.order_id.location_id.id
+    def _prepare_order_line_move(self, cr, uid, order, order_line, picking_id, *args):
         return {
-            'name': order_line.order_id.name + ': ' +(order_line.name or ''),
+            'name': order.name + ': ' +(order_line.name or ''),
             'product_id': order_line.product_id.id,
             'product_qty': order_line.product_qty,
             'product_uos_qty': order_line.product_qty,
@@ -453,27 +451,33 @@ class purchase_order(osv.osv):
             'product_uos': order_line.product_uom.id,
             'date': order_line.date_planned,
             'date_expected': order_line.date_planned,
-            'location_id': loc_id,
-            'location_dest_id': dest,
+            'location_id': order.partner_id.property_stock_supplier.id,
+            'location_dest_id': order.location_id.id,
             'picking_id': picking_id,
-            'address_id': order_line.order_id.dest_address_id.id or order_line.order_id.partner_address_id.id,
+            'address_id': order.dest_address_id.id or order.partner_address_id.id,
             'move_dest_id': order_line.move_dest_id.id,
             'state': 'draft',
             'purchase_line_id': order_line.id,
-            'company_id': order_line.order_id.company_id.id,
+            'company_id': order.company_id.id,
             'price_unit': order_line.price_unit
         }
 
-    def _create_pickings(self, cr, uid, order_lines, picking_id=False, *args):
+    def _create_pickings(self, cr, uid, order, order_lines, picking_id=False, *args):
         """
-        Create pickings for given order lines. Filtering the order lines allows to partition the delivery
-        over several pickings.
+        Creates pickings and appropriate stock moves for given order lines.
 
-        :param cr: database cursor
-        :param uid: current user id
-        :param order: sale order object
-        :param order_lines: sale order line objects
-        :param picking_id: id of picking to use evenually
+        If ``picking_id`` is provided, the stock moves will be added to it, otherwise
+        a standard outgoing picking will be created to wrap the stock moves, as returned
+        by :meth:`~._prepare_order_picking`.
+
+        Modules that wish to customize the procurements or partition the stock moves over
+        multiple stock pickings may override this method and call ``super()`` with
+        different subsets of ``order_lines`` and/or preset ``picking_id`` values.
+
+        :param browse_record order: purchase order to which the order lines belong
+        :param list(browse_record) order_lines: sale order line records to procure
+        :param int picking_id: optional ID of a stock picking to which the created stock moves
+                               will be added. A new picking will be created if ommitted.
         :return: True
         """
         picking_id = self.pool.get('stock.picking').create(cr, uid, self._prepare_order_picking(cr, uid, order, args))
@@ -482,9 +486,9 @@ class purchase_order(osv.osv):
             if not order_line.product_id:
                 continue
             if order_line.product_id.product_tmpl_id.type in ('product', 'consu'):
-                move = self.pool.get('stock.move').create(cr, uid, self._prepare_order_line_move(cr, uid, order_line, picking_id, args))
+                move = self.pool.get('stock.move').create(cr, uid, self._prepare_order_line_move(cr, uid, order, order_line, picking_id, args))
                 if order_line.move_dest_id:
-                    self.pool.get('stock.move').write(cr, uid, [order_line.move_dest_id.id], {'location_id': order_line.order_id.location_id.id})
+                    self.pool.get('stock.move').write(cr, uid, [order_line.move_dest_id.id], {'location_id': order.location_id.id})
                 todo_moves.append(move)
                 self.pool.get('stock.move').action_confirm(cr, uid, todo_moves)
                 self.pool.get('stock.move').force_assign(cr, uid, todo_moves)
@@ -494,10 +498,9 @@ class purchase_order(osv.osv):
         return picking_id
     
     def action_picking_create(self,cr, uid, ids, *args):
-        picking_id = False
         for order in self.browse(cr, uid, ids):
-            self._create_pickings(cr, uid, [order_line for order_line in order.order_line], False, args)
-        return picking_id
+            picking_id = self._create_pickings(cr, uid, order, [order_line for order_line in order.order_line], False, args)
+        return picking_id #FIXME this is brittle to assume there is only 1 picking_id, but has been kept for API compatibility
 
     def copy(self, cr, uid, id, default=None, context=None):
         if not default: