diff --git a/addons/sale/stock.py b/addons/sale/stock.py
index 653b147d3d0..618867821fb 100644
--- a/addons/sale/stock.py
+++ b/addons/sale/stock.py
@@ -48,6 +48,11 @@ class stock_picking(osv.osv):
         else:
             return super(stock_picking, self).get_currency_id(cursor, user, picking)
 
+    def _get_partner_to_invoice(self, cr, uid, picking, context=None):
+        if picking.sale_id:
+            return picking.sale_id.partner_id
+        return super(stock_picking, self)._get_partner_to_invoice(cr, uid, picking, context=context)
+
     def _get_payment_term(self, cursor, user, picking):
         if picking.sale_id and picking.sale_id.payment_term:
             return picking.sale_id.payment_term.id
@@ -195,4 +200,4 @@ class stock_picking(osv.osv):
                     })
         return result
 
-# vim:expandtab:smartindent:tabstop=4:softtabstop=4:shiftwidth=4:
\ No newline at end of file
+# vim:expandtab:smartindent:tabstop=4:softtabstop=4:shiftwidth=4:
diff --git a/addons/stock/stock.py b/addons/stock/stock.py
index ce344804347..c1a334a4b6d 100644
--- a/addons/stock/stock.py
+++ b/addons/stock/stock.py
@@ -874,6 +874,13 @@ class stock_picking(osv.osv):
     def get_currency_id(self, cr, uid, picking):
         return False
 
+    def _get_partner_to_invoice(self, cr, uid, picking, context=None):
+        """ Gets the partner that will be invoiced
+        Note that this function is inherited in the sale module
+        @return: partner object
+        """
+        return picking.address_id and picking.address_id.partner_id
+
     def _get_payment_term(self, cr, uid, picking):
         """ Gets payment term from partner.
         @return: Payment term
@@ -1030,7 +1037,7 @@ class stock_picking(osv.osv):
         for picking in self.browse(cr, uid, ids, context=context):
             if picking.invoice_state != '2binvoiced':
                 continue
-            partner =  picking.address_id and picking.address_id.partner_id
+            partner = self._get_partner_to_invoice(cr, uid, picking, context=context)
             if not partner:
                 raise osv.except_osv(_('Error, no partner !'),
                     _('Please put a partner on the picking list if you want to generate invoice.'))