re-mounting front plate, not sure how to fix without drilling new holes... Options

[saleeka]

I've got a dilemma... My front plate's bolts are falling out of their mounting brackets, and only the far right bolt seems to be the reason why my plate hasn't flew off completely yet. The two middle bolts are barely long enough to fit into the bumper, but the outer bolts are much longer (I haven't removed the plate completely yet- don't have the tools here at work, and I’m also afraid that I might not be able to get the plate to stay on again once it does come all the way off...). I'm assuming that there should be a nut attached to the end of the bold on the outer mounts, but I can't figure out how I’m supposed to get behind the bumper to screw one on? Anyone know what is going on here, or suggestions on how to fix the plate without drilling any new holes?