I think the best thing to do is to try and get hold of new clips. Install them on your rubber strip and then push the bayonet fitting into the hole in the sill. Removing the old ones will mean that you'll have to either drill out / pull out or push through into the sills. I guess the clips are only meant to be used once.

I think gluing is a great alternative as long as the surface underneath is stable and you never ever want to get them off again... if you do and the glue is as good as you say then you're gonna be stuffed!