Why not drill the bottom and use self threading machine screws??? Mount it to an Oak or other real Hardwood and punk it up... Steam Punk Style also if you remove all that rubber stuff in the bottom you might.. drive a couple of screws up from the bottom to use as anchors for an epoxy bond if as I suspect there is a cavity under the "Rubber Bottom". Either solution I offered is IMO permanent... So maybe someone else has another opinion... Perhaps do it right and drill and tap mounting holes on the bottom of the unit... Lotsa solutions... If the bottom is 'perfectly' flat you could even use Shu Goo. I used it to stick a diamond lap to a piece of white oak wood for my kitchen knife sharpener after JB Weld failed twice. Lotsa Idea's
Bob