Тестируемый код:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Channels;
using System.Text;

namespace ns_User {
  [ServiceContract]
  public interface IUser {
    [OperationContract]
    byte[] Test(byte[] Info);
  }
  //-- Локальная реализация функциональных контрактов 
  public partial class clsUser : ClientBase<ns_User.IUser>, ns_User.IUser {

    public clsUser() {
    }

    public clsUser(string endpointConfigurationName)
      : base(endpointConfigurationName) {
    }

    public clsUser(string endpointConfigurationName, string remoteAddress) :
      base(endpointConfigurationName, remoteAddress) {
    }

    public clsUser(string endpointConfigurationName, EndpointAddress remoteAddress) :
      base(endpointConfigurationName, remoteAddress) {
    }

    public clsUser(Binding binding, EndpointAddress remoteAddress)
      : base(binding, remoteAddress) {
    }

    public byte[] Test(byte[] Info) {
      return base.Channel.Test(Info);
    }
  }
}

   ns_User.clsUser user = new ns_User.clsUser(new NetTcpBinding(), new EndpointAddress(sURI));  
   byte[] xb = user.Test(new byte[2] { 3, 3 });

      NetTcpBinding binding = new NetTcpBinding();
      binding.Security.Mode = SecurityMode.None;
      binding.TransferMode = TransferMode.Buffered;
      ns_User.clsUser user = new ns_User.clsUser(binding, new EndpointAddress(sURI));
      byte[] xb = user.Test(new byte[2] { 3, 3 });