You will have to take out the module and find a board that will fit inside. You can take out the module through the front of the light by unscrewing the module out.
If you have a bare P7 emitter handy, the C2 is a great host. Just need to widen the reflector opening to 9mm. Kai has a direct drive multi mode board that fits the pill. Use it in conjunction with one 18650, and you're in big business.