diff --git a/addons/stock_account/stock.py b/addons/stock_account/stock.py
index 509bd91f173..db08ba39eb4 100644
--- a/addons/stock_account/stock.py
+++ b/addons/stock_account/stock.py
@@ -192,7 +192,7 @@ class stock_picking(osv.osv):
         invoice_obj = self.pool.get('account.invoice')
         return invoice_obj.create(cr, uid, vals, context=context)
 
-    def action_invoice_create(self, cr, uid, ids, journal_id=False, group=False, type='out_invoice', context=None):
+    def action_invoice_create(self, cr, uid, ids, journal_id, group=False, type='out_invoice', context=None):
         """ Creates invoice based on the invoice state selected for picking.
         @param journal_id: Id of journal
         @param group: Whether to create a group invoice or not
@@ -213,7 +213,31 @@ class stock_picking(osv.osv):
             invoices = self._invoice_create_line(cr, uid, moves, journal_id, type, context=context)
         return invoices
 
-    def _invoice_create_line(self, cr, uid, moves, journal_id=False, inv_type='out_invoice', context=None):
+    def _get_invoice_vals(self, cr, uid, key, inv_type, journal_id, origin, context=None):
+        if context is None:
+            context = {}
+        partner, currency_id, company_id, user_id = key
+        if inv_type in ('out_invoice', 'out_refund'):
+            account_id = partner.property_account_receivable.id
+            payment_term = partner.property_payment_term.id or False
+        else:
+            account_id = partner.property_account_payable.id
+            payment_term = partner.property_supplier_payment_term.id or False
+        return {
+            'origin': origin,
+            'date_invoice': context.get('date_inv', False),
+            'user_id': user_id,
+            'partner_id': partner.id,
+            'account_id': account_id,
+            'payment_term': payment_term,
+            'type': inv_type,
+            'fiscal_position': partner.property_account_position.id,
+            'company_id': company_id,
+            'currency_id': currency_id,
+            'journal_id': journal_id,
+        }
+
+    def _invoice_create_line(self, cr, uid, moves, journal_id, inv_type='out_invoice', context=None):
         invoice_obj = self.pool.get('account.invoice')
         move_obj = self.pool.get('stock.move')
         invoices = {}
@@ -222,30 +246,11 @@ class stock_picking(osv.osv):
             origin = move.picking_id.name
             partner, user_id, currency_id = move_obj._get_master_data(cr, uid, move, company, context=context)
 
-            key = (partner.id, currency_id, company.id, user_id)
+            key = (partner, currency_id, company.id, user_id)
 
             if key not in invoices:
                 # Get account and payment terms
-                if inv_type in ('out_invoice', 'out_refund'):
-                    account_id = partner.property_account_receivable.id
-                    payment_term = partner.property_payment_term.id or False
-                else:
-                    account_id = partner.property_account_payable.id
-                    payment_term = partner.property_supplier_payment_term.id or False
-
-                invoice_vals = {
-                    'origin': origin,
-                    'date_invoice': context.get('date_inv', False),
-                    'user_id': user_id,
-                    'partner_id': partner.id,
-                    'account_id': account_id,
-                    'payment_term': payment_term,
-                    'type': inv_type,
-                    'fiscal_position': partner.property_account_position.id,
-                    'company_id': company.id,
-                    'currency_id': currency_id,
-                    'journal_id': journal_id,
-                }
+                invoice_vals = self._get_invoice_vals(cr, uid, key, inv_type, journal_id, origin, context=context)
                 invoice_id = self._create_invoice_from_picking(cr, uid, move.picking_id, invoice_vals, context=context)
                 invoices[key] = invoice_id