I like Shoe Goo for stuff like that since (a) it bonds to rubber and (b) it is flexible instead of brittle.
That being said, I have used the built-in option on the alarm so I don't have to use the fob anymore. I just lock/unlock with the mechanical key. I leave the fob in the car just in case something resets and I need it, but that's not happened yet.
I broke two of the rubber pieces and went with this solution and it really classed up the keys. I think the design is supposed to be reminiscent of the spoke on the sport pack wheels. Looks great, feels great and I never have to worry about replacing it again.