That is basically using a picaxe chip. You would have to program the macros using the picaxe software similar to the picaxe project already on X-S, but using a 14M and expanding the program to the other buttons. It will require learning how the picaxe works etc etc.
The nice thing about the picaxe is that it can be reprogrammed while still inside the controller and powered by the batteries. A regular PIC cannot be programmed without detaching the lines from the controller somehow.
The bad thing about the picaxe is how many resources are consumed to run the picaxe OS (for lack of a better description). Basically, you lose all of the PICs timers, hardware interupts, and other useful finctions that make a PIC versatile. For example, the picaxe replaces the internal hardware interupt pins by replacing them with constantly polled routines. Also, there are no true timers. You have 'WAit' statements where a register is loaded with a count down value and the chip sits and spins until the count down is done. Nothing else can happen during this time.
