Bumper removal question...

Alright, I feel stupid for having to ask this, but where are the bolts holding on the rear bumper on a 1990 240SX? I have been looking under there with a flashlight for an hour and I can't find them. I need to get at the plate behind it to replace it, there is some rust on it that has weakened it somewhat and I feel I should put on a newer one. I already have the part from a junkyard, I just want to get the bumper off so I can change parts. Thanks in advance.