System.Net.NetworkCredential creds = GetNetWorkCredentials();
   BasicHttpBinding binding = new BasicHttpBinding();
   binding.Security.Mode = BasicHttpSecurityMode.Transport;
   binding.Security.Transport.ClientCredentialType = creds.httpClientCredentialType;
   ChannelFactory<Portal.WebServices.Internal.IPort> factory = new ChannelFactory<Portal.WebServices.Internal.IPort>(binding);
   factory.Credentials.Windows.ClientCredential = creds;
   factory.Credentials.UserName.UserName = creds.UserName;
   factory.Credentials.UserName.Password = creds.Password;
   Portal.WebServices.Internal.IPort proxy = factory.CreateChannel(new EndpointAddress(siteURL + "/_vti_bin/portal/Port.svc"));
   Portal.WebServices.Internal.FewObject[] invoices = proxy.GetInvoices(IDs);