Hi Ian,
Unfortunately, that API is different enough that my team is unable to be of much help. I know this may sound odd to you, but it would be like me trying to give advice on the Maps API. I could guess because code is code, but it wouldn't be much help. I'll start a private thread with you offline, and I'll try to route you to the appropriate people who would know how to help you.
Best,
Nadine, AdWords API Team