Вот так я настраиваю клиента из кода
var binding = new BasicHttpBinding(BasicHttpSecurityMode.TransportCredentialOnly);
binding.Security.Transport.ClientCredentialType = HttpClientCredentialType.Windows;
binding.Security.Transport.ProxyCredentialType = HttpProxyCredentialType.None;
binding.MaxBufferSize = Int32.MaxValue;
binding.MaxReceivedMessageSize = Int32.MaxValue;
binding.ReaderQuotas.MaxDepth = Int32.MaxValue;
binding.ReaderQuotas.MaxStringContentLength = Int32.MaxValue;
binding.ReaderQuotas.MaxArrayLength = Int32.MaxValue;
binding.ReaderQuotas.MaxBytesPerRead = Int32.MaxValue;
binding.ReaderQuotas.MaxNameTableCharCount = Int32.MaxValue;
BnsApiClient client = new BnsApiClient(binding, new EndpointAddress("http://mysite/Hello.svc"));