What glue for floor support?

["K M" <symbiotic@hotmail.com>]

I need to remove and fix that steel support that runs beneath the rear 
bolts of the seats, over the tranny hump -=-= from one side to the other 
(the one that John has on the website that is rusted away, it's around 
12 inches wide and spans the width of the car).  That piece is held in 
place by pop rivets and some kind of glue. Does anyone know a good glue 
for this? Thanks, Kim.