You may want to use Apache Axis (widely used). The Jt framework has a Web services adapter based on Axis. This should greatly expedite/simplify your efforts. Jt also provides built-in support for XML. The invocation of your web service would look like the following (a few simple lines of code).
Using the web service is like using a local class (thanks to the Jt Web services Adapter). The Web services adapter takes care of all the complexities associated with using a Web service. For instance you don't need to define an additiona WSDL, deal with service a parameters. or do conversions.
JtWebServicesAdapter myService;
JtMessage msg = new JtMessage ("XML");
// Create the Jt Web service Adapter
myService = (JtWebServicesAdapter) main.createObject ("Jt.axis.JtWebServicesAdapter",
"service");
// Set the service url property
main.setValue (myService, "url",
"http://localhost:8080/axis/services/JtAxisService");
// Create a remote instance of your class. The Jt Web service adaptor
// can be used to create remote instances of a class.
myService.createObject ("com.package.anyclass", "remoteClass");
// Send XML document to the remote class
msg.content ("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n .....");
Object reply = myService.sendMessage ("remoteClass", msg);
The following links should give you additional info
https://jt.dev.java.net/ http://www.fsw.com/Jt/Jt.htm (Jt documentation)