the next thing to look at, would be to think about gluing spacers of the appropriate shape and thickness, which would have to be made of ???, to the molding, or attach to the body, and try 3m tape.
unless, of course, you could try a completely different type of clip that fit the molding and attached to the body in the same manner as the original.
this may take some time at a good auto body supply company, or using someone's creative imagination.
there is a solution out there for this trim. it just has to be found.