I have had mine in my spare tire for over a year now with no light... The P/O had it there held on by a bailing wire which was either going to fall off somewhere or get stolen.
I took a piece of plywood and cut it the to the footprint of the license plate. I then drilled a hole through the center and ran a bolt through it long enough to go through the center of the rim. Then I ran a nut up the bolt to the back of the plywood.
Once this was completed I took a piece of scrap steel the was 2" wide by 4" long and drilled a hole through the center. Then I placed the plywwod with the bolt into the rim and placed the bracket onto the bolt on the back side of the rim. Then I ran a lock washer and nut on to the bolt secring the bracket to the rim.
After this was done I placed the license plate to the board and ran 2 flat head wood screws into the 2 upper bolt holes on the plate.
License plate secure but no light.
NOTE: It is my intention to modify my rear bumper yet (again) to a Runck style bumper. This will allow it to have a swing out upper bar housing a tire carrier. I will drill this upper bar out to hold the license plate and it will have a light mounted for the plate in it at that time.
Hope this helps you,
Tux...