Mounting Front License Plate?
 

I bought my dad's '99 Marquis and need to put a front license plate on it. He lived in a state the didn't require a plate. There are four holes in the front bumper but they are not threaded. I bought a "License Plate Bracket" from a Ford dealer. It is a cheap piece of plastic that I looks like it should be bolted to the bottom holes on the bumper (They line up) but the holes aren't threaded. The plate slides into slots on the edges. The top holes in the plate line up with the upper holes BUT they are not threaded.

I tried rigging it and lost the plate

Does anyone know how the heck the bracket and plate are supposed to be mounted. My dear wife is all over my case about this since she got a warning ticket from the Ohio State Patrol.