I was able to get in contact with a developer from 37 Signals over the weekend. I ran into some troubles finding a solid way to process the responses when you post, get, or put data to/from the Basecamp API. Turns out, the documentation is out-dated, and there are some known inconsistencies.
So – now knowing some crucial information “from the horse’s mouth”, I know now how to properly process the responses. This will be implemented in version 1.2. I’ll keep you posted!