License plate mounting -- help!

[Michael McLaughlin]

When closing the tailgate on my 1999.5 A4 Avant yesterday, the license plate came off the car. Not surprising, exactly; the metal clips in the fiberglass tailgate panel looked like they enlarged the holes over 10 years. Anyway, short of replacing that fiberglass panel (if it's even possible), does anyone have any suggestions for how to go about mounting the plate? I'd like a solution that doesn't involve permanently attaching the plate to the car (i.e. adhesives). Any help would be greatly appreciated.

Thanks,
Mike