System.ServiceModel.EndpointAddress ep = new System.ServiceModel.EndpointAddress("http://сервер/sd/ws/files.1cws?wsdl");
                System.ServiceModel.BasicHttpBinding binding = new System.ServiceModel.BasicHttpBinding();

                binding.Security.Mode = System.ServiceModel.BasicHttpSecurityMode.TransportCredentialOnly;
                binding.Security.Transport.ClientCredentialType = System.ServiceModel.HttpClientCredentialType.Basic;

                Service.FilesPortTypeClient pk = new Service.FilesPortTypeClient(binding, ep);
                pk.ClientCredentials.UserName.UserName = "dvim";
                pk.ClientCredentials.UserName.Password = "пароль";

                pk.Open();

                Service.File fll  = pk.GetFile("00-00000109");// ВОТ ТУТ ПРОИСХОДИТ ОШИБКА

System.ServiceModel.EndpointAddress ep = new System.ServiceModel.EndpointAddress("http://сервер/sd/ws/files.1cws");