diff --git a/addons/sale/sale.py b/addons/sale/sale.py
index 119bee779aa..180a4fd8378 100644
--- a/addons/sale/sale.py
+++ b/addons/sale/sale.py
@@ -1230,19 +1230,16 @@ class sale_order_line(osv.osv):
         return self.product_id_change(cursor, user, ids, pricelist, product,
                 qty=qty, uom=uom, qty_uos=qty_uos, uos=uos, name=name,
                 partner_id=partner_id, lang=lang, update_tax=update_tax,
-                date_order=date_order, context=context)
+                date_order=date_order, fiscal_position=context.get('fiscal_position', False), context=context)
 
     def onchange_product_uom(self, cursor, user, ids, pricelist, product, qty=0,
                              uom=False, qty_uos=0, uos=False, name='', partner_id=False,
                              lang=False, update_tax=True, date_order=False, fiscal_position=False, context=None):
-        context = context or {}
-        lang = lang or ('lang' in context and context['lang'])
-        if not uom:
-            return {'value': {'price_unit': 0.0, 'product_uom' : uom or False}}
-        return self.product_id_change(cursor, user, ids, pricelist, product,
+        ctx = dict(context or {}, fiscal_position=fiscal_position)
+        return self.product_uom_change(cursor, user, ids, pricelist, product,
                                       qty=qty, uom=uom, qty_uos=qty_uos, uos=uos, name=name,
                                       partner_id=partner_id, lang=lang, update_tax=update_tax,
-                                      date_order=date_order, fiscal_position=fiscal_position, context=context)
+                                      date_order=date_order, context=ctx)
 
     def unlink(self, cr, uid, ids, context=None):
         if context is None: