i was looking into this also, but decided against it as it was a cheapo alarm, and if some chav decided to walk round a car park chancing it with one of these alarm gadgets that runs through loads of unlocking codes then he wud be straight into mine, so decided to leave the central locking out.
however, there are cables in each door you can crimp off, but this would be far too much hassle, so the best place to do it is at the actual pump in the boot, on the plug that connects into the pump there is a pin for a signal to unlock and lock the doors. I cannot remember off the top of my head which pins they were and i think i had to guess at them as the circuit diagrams kicking about doesnt give an explanation of the pins for the motor, but you can work it out quite easily
