Getting Response from WebService using SOAP

Hi,
After going through all the posts, I have built a Soap message, which will send a string to WS but while working on getting the ACK message back from WS, I am using,

IF ISCLEAR(XMLDOM) THEN 
              CREATE(XMLDOM); 
            XMLDOM.load(Connector.OutputStream); 
            XMLNode := XMLDOM.selectSingleNode('//valid'); 
            IF NOT ISCLEAR(XMLNode) THEN 
              Var := XMLNode.text; 
            CLEAR(XMLDOM); 
            CLEAR(Connector);

My concern is, will the above code read the respective ACK for which msg was sent. or is it requuired to put some timespan or message-id to get back the respective ack.

Please suggest.

Thanks & regards,
Vikas