Access xignite webserive with header authentication in Android?

package com.tuan;

import org.apache.http.Header;
import org.ksoap2.SoapEnvelope;
import org.ksoap2.serialization.SoapObject;
import org.ksoap2.serialization.SoapPrimitive;
import org.ksoap2.serialization.SoapSerializationEnvelope;
import org.ksoap2.transport.AndroidHttpTransport;
import org.ksoap2.transport.HttpTransportSE;
import org.kxml2.kdom.Element;
import org.kxml2.kdom.Node;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
 
public class Xignite_WSActivity extends Activity {
    /** Called when the activity is first created. */
	
	 private static final String SOAP_ACTION = "http://www.xignite.com/services/GetRealTimeCrossRate";
	    private static final String METHOD_NAME = "GetRealTimeCrossRate";
	    private static final String NAMESPACE = "http://www.xignite.com/services/";
	    private static final String URL = "http://www.xignite.com/xCurrencies.asmx";
	
	TextView tv;
	
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        tv=(TextView)findViewById(R.id.Textview01);
        //tao request
        SoapObject Request = new SoapObject(NAMESPACE, METHOD_NAME);
       
        //Is this code to access header properly ?
        Request.addProperty("Username", "onlyyou2011@yahoo.com");
        Request.addProperty("Password","12345qwert");
        Request.addProperty("Tracer","tuan123");
       
        Request.addProperty("From","USD");
        Request.addProperty("To","VND");

        SoapSerializationEnvelope soapEnvelope = new SoapSerializationEnvelope(SoapEnvelope.VER11);
     //   soapEnvelope.dotNet=true;
 
        
        soapEnvelope.setOutputSoapObject(Request);
        HttpTransportSE httpTransportSE = new HttpTransportSE(URL);
	    AndroidHttpTransport aht = new AndroidHttpTransport(URL);
    
       
       try {
    	   aht.call(SOAP_ACTION, soapEnvelope);
    	   httpTransportSE.call(SOAP_ACTION,soapEnvelope);
    	   SoapPrimitive resultString = (SoapPrimitive)soapEnvelope.getResponse();
    	
    	   tv.setText("Trang Thai"+resultString);
	} catch (Exception e) {
		// TODO: handle exception
		e.printStackTrace();
	}
        
    }
}