A lot of alarms have an output driver for the central locking. Have a sniff around with a 12V test light and see if you can find a wire out the back of the alarm that gives a flash as the alarm is activated or de-activated. I can't help with the mechanical interface, but on my old Mav it was easy to couple up the locking motor to the rod coming down from the lock push button. In contrast to the factory unit, I mounted mine as high as possible to reduce damage in river crossings.