The plot thickens... This is what Weaver had to say about the question:

The Next is a little involved first thing you do is sand the back of
the registration pad with 80 grit paper. Then get the PVC two part glue
and put a layer of glue on the pad and on the inflatable let it dry
completely then put another layer of glue on let it sit for a little
bit to the glue get tacky. Use a hair drier to warm up the pad and the
inflatable put the two pieces together rub the air bubbles out and
leave them alone for a couple of days.