Error Export Invoice PAC SF V6

Hola
Estoy probando el timbrado del CFDI con SF.

Los parámetros PAC son los siguientes:
URL -- http://testing.solucionfactible.com/ws/services/Timbrado?wsdl
Namespace -- http://timbrado.ws.cfdi.solucionfactible.com
Usuario -- <email address hidden>
Contraseña -- timbrado.SF.16672
Cetrificado link -- http://solucionfactible.com/sfic/resources/files/csdSAT-SF/prod/00001000000202864530.zip
Secuencia -- 1

Al ingresar a una factura que ya esta validada y después intentar timbrarla Export Invoice PAC SF V6 marca los siguientes errores:

Client Traceback (most recent call last):
  File "/opt/openerp/server/openerp/addons/web/http.py", line 204, in dispatch
    response["result"] = method(self, **self.params)
  File "/opt/openerp/server/openerp/addons/web/controllers/main.py", line 1132, in call_button
    action = self._call_kw(req, model, method, args, {})
  File "/opt/openerp/server/openerp/addons/web/controllers/main.py", line 1120, in _call_kw
    return getattr(req.session.model(model), method)(*args, **kwargs)
  File "/opt/openerp/server/openerp/addons/web/session.py", line 42, in proxy
    result = self.proxy.execute_kw(self.session._db, self.session._uid, self.session._password, self.model, method, args, kw)
  File "/opt/openerp/server/openerp/addons/web/session.py", line 30, in proxy_method
    result = self.session.send(self.service_name, method, *args)
  File "/opt/openerp/server/openerp/addons/web/session.py", line 103, in send
    raise xmlrpclib.Fault(openerp.tools.ustr(e), formatted_info)

Server Traceback (most recent call last):
  File "/opt/openerp/server/openerp/addons/web/session.py", line 89, in send
    return openerp.netsvc.dispatch_rpc(service_name, method, args)
  File "/opt/openerp/server/openerp/netsvc.py", line 292, in dispatch_rpc
    result = ExportService.getService(service_name).dispatch(method, params)
  File "/opt/openerp/server/openerp/service/web_services.py", line 626, in dispatch
    res = fn(db, uid, *params)
  File "/opt/openerp/server/openerp/osv/osv.py", line 188, in execute_kw
    return self.execute(db, uid, obj, method, *args, **kw or {})
  File "/opt/openerp/server/openerp/osv/osv.py", line 131, in wrapper
    return f(self, dbname, *args, **kwargs)
  File "/opt/openerp/server/openerp/osv/osv.py", line 197, in execute
    res = self.execute_cr(cr, uid, obj, method, *args, **kw)
  File "/opt/openerp/server/openerp/osv/osv.py", line 185, in execute_cr
    return getattr(object, method)(cr, uid, *args, **kw)
  File "/opt/openerp/server/openerp/addons/l10n_mx_facturae_pac_sf/wizard/wizard_export_invoice_pac_sf_v6.py", line 63, in upload_to_pac
    res = invoice_obj._upload_ws_file(cr, uid, context['active_ids'])
AttributeError: 'account.invoice' object has no attribute '_upload_ws_file'

Espero puedan orientarme un poco sobre que indican estos errores y como se pueden resolver.

Estoy usando la Versión 7.0-20131101-002547 de Openerp y la localizacion México lp:openerp-mexico-localization/7.0 revisión 321

De antemano muchas gracias