cannot create advance invoice in a SO

in a so, click on "Advance Invoice" set product and an amount :

Traceback (most recent call last):
  File "/home/aline/openerp/server/trunk/openerp/netsvc.py", line 440, in dispatch
    result = ExportService.getService(service_name).dispatch(method, auth, params)
  File "/home/aline/openerp/server/trunk/openerp/service/web_services.py", line 583, in dispatch
    res = fn(db, uid, *params)
  File "/home/aline/openerp/server/trunk/openerp/osv/osv.py", line 118, in wrapper
    return f(self, dbname, *args, **kwargs)
  File "/home/aline/openerp/server/trunk/openerp/osv/osv.py", line 172, in execute
    res = self.execute_cr(cr, uid, obj, method, *args, **kw)
  File "/home/aline/openerp/server/trunk/openerp/osv/osv.py", line 163, in execute_cr
    return getattr(object, method)(cr, uid, *args, **kw)
  File "/home/aline/openerp/addons/trunk/sale/wizard/sale_make_invoice_advance.py", line 70, in create_invoices
    'account_id': val['value']['account_id'],
KeyError: 'account_id'