That seems like it would be a lot of work to make it work.
I'm thinking there might be another system that that unit works with to actually move the door actuators?
I installed a keyless system into my 91.
I have central door locks (door actuators on 3 doors, none on the drivers door).
It cost me $15 for the keyless entry and $5 for a door actuator on eBay:
My keyless system:
http://www.ebay.ca/itm/Universal-Car-Re ... RTM2067269
You can even add remote keyless trunk (if it's a sedan). Just need a relay and another actuator.
Door actuator:
http://www.ebay.ca/itm/12V-Car-Auto-Pla ... 1e81c055dd
I also bought a beeper:
http://www.ebay.ca/itm/1XHigh-decibel-9 ... 58bc5e38c8
The brain has 2 spots for the lights to hook up to. Used one for the lights, and the other to the beeper.
Gives off a similar sound to the Subaru's and Toyota's lock and unlocking.
If you want an alarm, perhaps something like this:
http://www.ebay.com/itm/1-Way-Car-Vehic ... 419ad5e3dc
Just mount the door actuator, run the wiring, and mount the brain somewhere under the kick panel.
Here is a video I made after I installed it.
It's before I had the beeper and was using the old alarms siren instead:
https://www.youtube.com/watch?v=LR73ChEc0I0
And inside the door panel:
https://www.youtube.com/watch?v=PMGqohQCMv0
This write up might be helpful if you do decide to go this route:
http://bbs.legacycentral.org/viewtopic.php?f=19&t=42955
I know it's not exactly what you want, but, for the price and the ease of the install, I think it's probably a better way to go.