Next time, consider the Scotch product called 'Dual Lock'. It's very strong and sort of like super velcro. Radio Shack sells it in many stores, or motorcycle shops, sewing supply stores, etc. It's tiny mushroom shaped plastic pins that interlock when pressed together. I typically use it for motorcycle mounting of things I want to be able to quickly remove.
Tip: A little goes a long way. Don't cover the entire surface of what ever you are mounting. ;-) Kind of tough to get it off if you do that with a larger item like the scanguage.