There is a picture of my bumper mount install here:
http://homepage.mac.com/babiak1/Mods1.htm
I recently updated the install to a billet mount and heavy duty spring and sighly suggest if you bumper mount not to go with anything but a heavy duty setup, you'll end up for a drooping antenna in no time otherwise. I wish I could remember the vendor for my setup as it is really nice, best bet is to check around on the web.