diff --git a/addons/point_of_sale/static/src/js/models.js b/addons/point_of_sale/static/src/js/models.js
index 92276db60de..17278ed1bd9 100644
--- a/addons/point_of_sale/static/src/js/models.js
+++ b/addons/point_of_sale/static/src/js/models.js
@@ -324,20 +324,21 @@ function openerp_pos_models(instance, module){ //module is instance.point_of_sal
         // it returns a deferred that succeeds after having tried to send the order and all the other pending orders.
         push_order: function(order) {
             var self = this;
-            this.proxy.log('push_order',order.export_as_JSON());
-            var order_id = this.db.add_order(order.export_as_JSON());
+
+            if(order){
+                this.proxy.log('push_order',order.export_as_JSON());
+                this.db.add_order(order.export_as_JSON());
+            }
+            
             var pushed = new $.Deferred();
 
-            this.set('synch',{state:'connecting', pending:self.db.get_orders().length});
-
             this.flush_mutex.exec(function(){
-                var flushed = self._flush_all_orders();
+                var flushed = self._flush_orders(self.db.get_orders());
 
-                flushed.always(function(){
+                flushed.always(function(ids){
+                    console.log('pushed orders:',ids);
                     pushed.resolve();
                 });
-
-                return flushed;
             });
             return pushed;
         },
@@ -361,8 +362,6 @@ function openerp_pos_models(instance, module){ //module is instance.point_of_sal
 
             var order_id = this.db.add_order(order.export_as_JSON());
 
-            this.set('synch',{state:'connecting', pending:self.db.get_orders().length});
-
             this.flush_mutex.exec(function(){
                 var done = new $.Deferred(); // holds the mutex
 
@@ -373,7 +372,7 @@ function openerp_pos_models(instance, module){ //module is instance.point_of_sal
                 // things will happen as a duplicate will be sent next time
                 // so we must make sure the server detects and ignores duplicated orders
 
-                var transfer = self._flush_order(order_id, {timeout:30000, to_invoice:true});
+                var transfer = self._flush_orders([self.db.get_order(order_id)], {timeout:30000, to_invoice:true});
                 
                 transfer.fail(function(){
                     invoiced.reject('error-transfer');
@@ -382,10 +381,12 @@ function openerp_pos_models(instance, module){ //module is instance.point_of_sal
 
                 // on success, get the order id generated by the server
                 transfer.pipe(function(order_server_id){    
+
                     // generate the pdf and download it
                     self.pos_widget.do_action('point_of_sale.pos_invoice_report',{additional_context:{ 
                         active_ids:order_server_id,
                     }});
+
                     invoiced.resolve();
                     done.resolve();
                 });
@@ -397,62 +398,33 @@ function openerp_pos_models(instance, module){ //module is instance.point_of_sal
             return invoiced;
         },
 
-        // attemps to send all pending orders ( stored in the pos_db ) to the server,
-        // and remove the successfully sent ones from the db once
-        // it has been confirmed that they have been sent correctly.
-        flush: function() {
+        // wrapper around the _save_to_server that updates the synch status widget
+        _flush_orders: function(orders, options) {
             var self = this;
-            var flushed = new $.Deferred();
 
-            this.flush_mutex.exec(function(){
-                var done = new $.Deferred();
+            this.set('synch',{ state: 'connecting', pending: orders.length});
 
-                self._flush_all_orders()
-                    .done(  function(){ flushed.resolve();})
-                    .fail(  function(){ flushed.reject(); })
-                    .always(function(){ done.resolve();   });
-
-                return done;
-            });
-
-            return flushed;
-        },
-
-        // attempts to send the locally stored order of id 'order_id'
-        // the sending is asynchronous and can take some time to decide if it is successful or not
-        // it is therefore important to only call this method from inside a mutex
-        // this method returns a deferred indicating wether the sending was successful or not
-        // there is a timeout parameter which is set to 2 seconds by default. 
-        _flush_order: function( order_id, options) {
-            return this._flush_all_orders([this.db.get_order(order_id)], options);
-        },
-        
-        // attempts to send all the locally stored orders. As with _flush_order, it should only be
-        // called from within a mutex. 
-        // this method returns a deferred that always succeeds when all orders have been tried to be sent,
-        // even if none of them could actually be sent. 
-        _flush_all_orders: function () {
-            var self = this;
-            self.set('synch', {
-                state: 'connecting',
-                pending: self.get('synch').pending
-            });
-            return self._save_to_server(self.db.get_orders()).done(function () {
+            return self._save_to_server(orders, options).done(function (server_ids) {
                 var pending = self.db.get_orders().length;
+
                 self.set('synch', {
                     state: pending ? 'connecting' : 'connected',
                     pending: pending
                 });
+
+                return server_ids;
             });
         },
 
         // send an array of orders to the server
         // available options:
         // - timeout: timeout for the rpc call in ms
+        // returns a deferred that resolves with the list of
+        // server generated ids for the sent orders
         _save_to_server: function (orders, options) {
             if (!orders || !orders.length) {
                 var result = $.Deferred();
-                result.resolve();
+                result.resolve([]);
                 return result;
             }
                 
@@ -474,10 +446,11 @@ function openerp_pos_models(instance, module){ //module is instance.point_of_sal
                     shadow: !options.to_invoice,
                     timeout: timeout
                 }
-            ).then(function () {
+            ).then(function (server_ids) {
                 _.each(orders, function (order) {
                     self.db.remove_order(order.id);
                 });
+                return server_ids;
             }).fail(function (unused, event){
                 // prevent an error popup creation by the rpc failure
                 // we want the failure to be silent as we send the orders in the background
diff --git a/addons/point_of_sale/static/src/js/widgets.js b/addons/point_of_sale/static/src/js/widgets.js
index 5db12165737..66130a7740c 100644
--- a/addons/point_of_sale/static/src/js/widgets.js
+++ b/addons/point_of_sale/static/src/js/widgets.js
@@ -840,7 +840,7 @@ function openerp_pos_widgets(instance, module){ //module is instance.point_of_sa
                 self.set_status(synch.state, synch.pending);
             });
             this.$el.click(function(){
-                self.pos.flush();
+                self.pos.push_order();
             });
         },
     });
@@ -1005,7 +1005,7 @@ function openerp_pos_widgets(instance, module){ //module is instance.point_of_sa
             
                 self.$('.loader').animate({opacity:0},1500,'swing',function(){self.$('.loader').addClass('oe_hidden');});
 
-                self.pos.flush();
+                self.pos.push_order();
 
             }).fail(function(){   // error when loading models data from the backend
                 return new instance.web.Model("ir.model.data").get_func("search_read")([['name', '=', 'action_pos_session_opening']], ['res_id'])