Android中的肥皂网服务请求和响应？

我是一个非常新的Android Soap Web服务我对使用Ksoap2在Android中使用soap web服务有一些了解，因为我编写了以下代码：使用ksoap2.jar我从WSDL文件中获取了名称空间和方法名称 .

package com.soapwebservices.pack;

import org.ksoap2.SoapEnvelope;
import org.ksoap2.serialization.SoapObject;
import org.ksoap2.serialization.SoapSerializationEnvelope;
import org.ksoap2.transport.HttpTransportSE;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;

public class SampleWSExampleActivity extends Activity {
    private static final String TAG = null;
    /** Called when the activity is first created. */
      final String NAMESPACE = "urn:sap-com:document:sap:soap:functions:mc-style";
         final String URL = "http://***************:8000/sap/bc/srt/wsdl/srvc_14DAE9C8D79F1EE196F1FC6C6518A345/wsdl11/allinone/ws_policy/document?sap-client=800&sap-user=********&sap-password=*******";
          final String METHOD_NAME = "Z_GET_CUST_GEN";
         final String SOAP_ACTION = "urn:sap-com:document:sap:soap:functions:mc-style/Z_GET_CUST_GEN";
      //    private static final String[] sampleACTV = new String[];
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME);        
        SoapSerializationEnvelope envelope = 
            new SoapSerializationEnvelope(SoapEnvelope.VER11);

        envelope.setOutputSoapObject(request);
        HttpTransportSE androidHttpTransport = new HttpTransportSE(URL);

        try {
            androidHttpTransport.call(SOAP_ACTION, envelope);
            SoapObject resultsRequestSOAP = (SoapObject) envelope.bodyIn;

            System.out.println("THE SOAP RESPONSE"+resultsRequestSOAP);

            //ACTV.setHint("Received :" + resultsRequestSOAP.toString());
        } catch (Exception e) {


            e.printStackTrace();
        }
    }
}  

when i run this program i got the following Exception but in some examples i got the success please see once and let me know where i am doing the mistake 


08-20 15:21:40.296: WARN/System.err(1668): org.xmlpull.v1.XmlPullParserException: expected: START_TAG {http://schemas.xmlsoap.org/soap/envelope/}Envelope (position:START_TAG <{http://schemas.xmlsoap.org/wsdl/}wsdl:definitions targetNamespace='urn:sap-com:document:sap:soap:functions:mc-style'>@1:686 in java.io.InputStreamReader@4052f658) 

How can handle that exc