What do you mean your stunt mode broke? If just the switch broke, you can go to an electronics store and just get another one. It's a simple 3 wire switch with a nut. No need to buy another one.
And as far as I can remember, you can program to another switch, but I highly suggest against doing that. Always leave your idle up switch and your hold switch in the same locations at all times. That way if something happens, you don't reach for the wrong switch.