I had the same problem with my 05 Southwind, Screws kept breaking off!
I used some bigger self tapping screws and made sure they were stainless.
I also added a little med strength lok-tite to the screws and I haven't had a problem since
LONG LONESOME HIGHWAY
Going down that long lonesome highway,Bound for the mountains and the plains
Michael Parks / Then Came Bronson - 1969