go on tgr and search for bending brakes or bending p18 fks brakes. There is even a video topic on there. basically since u can buy replacements for ur bindings, u might as well try it, cause if u break one, oh well then just buy a pair no biggie.
bending them will work just as well as not, and it should be pretty easy on px12's
Heating the metal up and letting them cool will cause them to become harder, but also more brittle. Ideally you should heat them, bend them, heat them up again, then quench them to maintain some sort of temper, otherwise they'll be fragile.
Myself, I just bend the crap out of them until they fit.