Thanks Z, here's my Idea:
https://img75.imageshack.us/img75/1301/tempyc8.th.png
use booleans with this piece of geometry on a smoothed mash.
I don't even bother with cleaning the geometry on this one because it doesn't really matter (I think, we'll see when the time to render it comes )
I'm starting to model the door now, and will post some progress soon (I hope)

Benny