Hi everyone! I've got another problem: I tried to remove the ceiling yesterday - but it seems this can't be done porpably without damageing unless the ledge above the doors is removed. The ledge looks like it is cliped, but I tried tu unclip it but it didn't come of and I didn't want to pull so hard 'cause I was afraid of breaking it. Does anybody know how to remove it?

I think you are talking about the trim that goes up the A pillar and back to the B pillar. These trim pieces need to be pulled inward and up in order to pull down. I don't remember exactly but there are 3 clips along the top and 3 more along the A pillar. Locate the clips by gently pulling inward. There will be a noticable amount less flex in the plastic where the clips are. It is at this point that you pull in/up and then down. The trim kinda hangs on the clips like a hanger hangs on a closet rod. Same release motion just not as much travel.