C++ Builder6调用C#写的WebService出錯,该如何解决

C++ Builder6调用C#写的WebService出錯
C++ Builder6调用C#写的WebService出錯,提示:
  Object reference not set to an instance of an object.
这个WebService用C#写的应用程序可以正常调用.

在网上找了一个WebService测试了下:  
  http://www.webxml.com.cn/WebServices/MobileCodeWS.asmx
   调用getMobileCodeInfo 函数 
    返回:手机号码错误 http://www.webxml.com.cn

C++ Builder代码:
  Unit1.cpp
  

//---------------------------------------


#include <vcl.h>

#pragma hdrstop


#include "Unit1.h"

//---------------------------------------

#pragma package(smart_init)

#pragma resource "*.dfm"

TForm1 *Form1;

//---------------------------------------

__fastcall TForm1::TForm1(TComponent* Owner)

        : TForm(Owner)

{

}

//---------------------------------------

_di_MobileCodeWSSoap TForm1::GetWebService()

{

        if(!ss)

        {

                HTTPRIO1->QueryInterface(ss);

        }

        return ss;

}


void __fastcall TForm1::Button1Click(TObject *Sender)

{

        AnsiString mobileid = Memo2->Text.Trim();

        if(getMobileCodeInfo)

        {

                Memo1->Text = "Mobile ID:" + mobileid;

                Memo1->Lines->Add(getMobileCodeInfo->getMobileCodeInfo(mobileid," "));

        }

}

//---------------------------------------

Unit1.h

//---------------------------------------


#ifndef Unit1H

#define Unit1H

//---------------------------------------

#include <Classes.hpp>

#include <Controls.hpp>

#include <StdCtrls.hpp>

#include <Forms.hpp>

#include <Rio.hpp>

#include <SOAPHTTPClient.hpp>

#include "MobileCodeWS.h"

//---------------------------------------

class TForm1 : public TForm

{

__published:	// IDE-managed Components

        TMemo *Memo1;

        TEdit *Edit1;

        TMemo *Memo2;

        TButton *Button1;

        THTTPRIO *HTTPRIO1;

        void __fastcall Button1Click(TObject *Sender);

private:	// User declarations

public:		// User declarations

        __fastcall TForm1(TComponent* Owner);