This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
In cases like these it's useful to examine the SOAP that gets sent over the wire. Either a tool like tcpmon (comes with Axis) can show it, or you could save the server response to a file before sending it, and examine its contents.