Got your email..........I gather you have the vaccuum central locking system. My cabrio has electric motors in each door so its a little different, however the Mk2 that I pulled the Toad alarm out of had the vaccuum system. What they did there is just put a motor in the drivers door to pull down the lock. When the lock is pulled down by the motor it will activate the vaccuum system and pull the rest of the locks.......does that make sense?
I still have the drivers door motor connected to the vaccuum system so I could take a photo of it for you so that you can see how it works.
What remote system have you got? Working out the wiring for that could be tricky.