Consumming using win http services

I have clients who want to access a web service by sending a string using either win http services methods open & send or the following code. What do I have to modify in my win api code to allow this functionality. In both cases the string is passed to the service by a send() or similar method.

Client Code:

vendorRequest = buildRequestXML();

PrintWriter out = new PrintWriter(conn.getOutputStream());

out.println(vendorRequest);

out.close();