remounting front license plate?

My daughter is driving the P5 now in another state, and the other day she hit an empty can on the highway, almost dead center. It apparently fell off a truck or something. Anyway, she says the bumper looks OK but one of the two screws that hold the license plate in position is gone, and the license plate is dangling on the other one. Since the car is 1800 miles away I can't go look at it, so I'm not sure what to tell her about how to fix it. Do the license plate screws go into anything special, or are they just screwed into the foam on the bumper? (I'm guessing that might be the case, because that would explain how a light collision could break a screw loose without otherwise damaging anything else.) What is the suggested fix for this? Longer screw, bigger diameter screw, fill the hole with something and then put another screw back in, or ...?

Thanks.

If the car is a beater and you don't care about putting new holes in the bumper, just have her screw the plate in using 1 1/2" screws slightly to the left or right of the original holes. You can screw right in to the bumper. The plate will cover the old holes anyways