Hehe... yeah, so I stated that it would be pretty much trivial - I was soooo wrong
Well, conceptually, it is. But practically, it had me banging my head against the wall for about a week - not because it's really difficult, but because the configuration is spread over 3 different files, which *all* have to be patched to make it work correctly.
So now I finally figured out which changes have to be made. And I'm only back at my previous statement: the configuration interface is the part that is really difficult to get right.
Anyway, here is a screenshot of the current development (= not finished) version:
