I've written a few classes for nusoap sucessfully. If you link me to the API Function description of GetPPDData I'll be glad to have a look.
EDIT: I googled it and only found a duplicate of this post on another forum. I noticed the MS kit works for you in that post which is kinda funny to me. Cause when first read your post I laughed to myself thinking, what, MS lets nusoap clients access their server? They always reinvent the wheel and screw it up in their own incarnation of perfectly working and defined APIs.
But anyhow, if you have a link to the SDK and API, I'm even more curious now.