[DanEC]

It would have to be a high temp resistant adhesive but I'm not sure I would try that. Too much to risk if it comes loose again and breaks up or shucks the lining out of the caliper and the backing plate scores the rotor. Since you are obviously trying to improve braking performance, why not source out some high quality, riveted pads to replace those?

Please post some photos of your upgrade - I think a number of readers would be interested in your project to install vented discs.