Parsing a string variable as baseURL

I want to use a httpService request to read an XML file which retreives data from the xml file which is the path i want to parse to the Super_Sample1 Class / Function rather than having it as a hard coded path.

I can read the XML file and display the path in a text field.

Once the XML file resoonse is received it then triggers the HTTPService to receive the data using the path from the XLM file.

I get an error when ever I modify the hard coded path to a variable like the {mypath.lastResult} which is where the XML path is returned to.

I hope I explained this clear enough.

Any suggestions on parsing this path to the Function shown below?

package services.sample1

{

import com.adobe.fiber.core.model_internal;

import com.adobe.fiber.services.wrapper.HTTPServiceWrapper;

import mx.rpc.AbstractOperation;

import mx.rpc.AsyncToken;

import mx.rpc.http.HTTPMultiService;

import mx.rpc.http.Operation;

[ExcludeClass]

internal class _Super_Sample1 extends com.adobe.fiber.services.wrapper.HTTPServiceWrapper

{

    // Constructor

    public function _Super_Sample1()

    {

        // initialize service control

        _serviceControl = new mx.rpc.http.HTTPMultiService("http://ibm/sample01-debug/"); <<<<<< This is what I want to replace with a string variable

         var operations:Array = new Array();

         var operation:mx.rpc.http.Operation;

         var argsArray:Array;

         operation = new mx.rpc.http.Operation(null, "Operation");

         operation.url = "mytest.php";

         operation.method = "GET";

         operation.resultType = Object;

         operations.push(operation);

         _serviceControl.operationList = operations; 

         preInitializeService();

         model_internal::initialize();

    }

    //init initialization routine here, child class to override

    protected function preInitializeService():void

    {

    }

    /**

      * This method is a generated wrapper used to call the 'Operation' operation. It returns an mx.rpc.AsyncToken whose

      * result property will be populated with the result of the operation when the server response is received.

      * To use this result from MXML code, define a CallResponder component and assign its token property to this method's return value.

      * You can then bind to CallResponder.lastResult or listen for the CallResponder.result or fault events.

      *

      * @see mx.rpc.AsyncToken

      * @see mx.rpc.CallResponder

      *

      * @return an mx.rpc.AsyncToken whose result property will be populated with the result of the operation when the server response is received.

      */

    public function Operation() : mx.rpc.AsyncToken

    {

        var _internal_operation:mx.rpc.AbstractOperation = _serviceControl.getOperation("Operation");

                    var _internal_token:mx.rpc.AsyncToken = _internal_operation.send() ;

        return _internal_token;

    }

}

}