Thank you Uwe.
Guess i have to get back to the drawing board. For now i will use the myFoot.index - myFoot.parent.footnotes[0].index trick to get stuff working on a story based case.
Basicly i need to create custom footnote numbering that restarts based on paragraph styles, and combines numbering like 1), 2), 3) with *) **) and 1a), 1b), 2a) etc.
I keep wanting to get started with the Indesign SDK and C++, and this seems like a good way to jump in.