diff --git a/addons/sale/wizard/sale_make_invoice.py b/addons/sale/wizard/sale_make_invoice.py
index 2d5bd29b2c2..d4757ae43ff 100644
--- a/addons/sale/wizard/sale_make_invoice.py
+++ b/addons/sale/wizard/sale_make_invoice.py
@@ -20,7 +20,6 @@
 
 from openerp.osv import fields, osv
 from openerp.tools.translate import _
-from openerp import netsvc
 
 class sale_make_invoice(osv.osv_memory):
     _name = "sale.make.invoice"
@@ -40,7 +39,7 @@ class sale_make_invoice(osv.osv_memory):
         record_id = context and context.get('active_id', False)
         order = self.pool.get('sale.order').browse(cr, uid, record_id, context=context)
         if order.state == 'draft':
-            raise osv.except_osv(_('Warning!'),'You cannot create invoice when sales order is not confirmed.')
+            raise osv.except_osv(_('Warning!'), 'You cannot create invoice when sales order is not confirmed.')
         return False
 
     def make_invoices(self, cr, uid, ids, context=None):
@@ -51,9 +50,11 @@ class sale_make_invoice(osv.osv_memory):
         if context is None:
             context = {}
         data = self.read(cr, uid, ids)[0]
-        wf_service = netsvc.LocalService("workflow")
-        for id in context.get(('active_ids'), []):
-            wf_service.trg_validate(uid, 'sale.order', id, 'manual_invoice', cr)
+        for sale_order in context.get(('active_ids'), []):
+            if sale_order.state != 'manual':
+                raise osv.except_osv(_('Warning!'), "You shouldn't manually invoice the following sale order %s" % (sale_order.name))
+
+        order_obj.action_invoice_create(cr, uid, context.get(('active_ids'), []), data['grouped'], date_invoice=data['invoice_date'])
 
         for o in order_obj.browse(cr, uid, context.get(('active_ids'), []), context=context):
             for i in o.invoice_ids:
@@ -62,7 +63,7 @@ class sale_make_invoice(osv.osv_memory):
         result = mod_obj.get_object_reference(cr, uid, 'account', 'action_invoice_tree1')
         id = result and result[1] or False
         result = act_obj.read(cr, uid, [id], context=context)[0]
-        result['domain'] = "[('id','in', ["+','.join(map(str,newinv))+"])]"
+        result['domain'] = "[('id','in', [" + ','.join(map(str, newinv)) + "])]"
 
         return result
 
diff --git a/addons/sale/wizard/sale_make_invoice.xml b/addons/sale/wizard/sale_make_invoice.xml
index 14e11e228bc..de680feb049 100644
--- a/addons/sale/wizard/sale_make_invoice.xml
+++ b/addons/sale/wizard/sale_make_invoice.xml
@@ -8,6 +8,7 @@
                 <form string="Create invoices" version="7.0">
                     <separator colspan="4" string="Do you really want to create the invoice(s)?" />
                     <group>
+                        <field name="grouped"/>
                         <field name="invoice_date"/>
                     </group>
                     <footer>