You advertise as a certified alarm installer?
Why aren't there door lock switches on your door panel? How does the car have power door locks?
Go to the actuator and trace the wires back. You verify the wires with a multimeter. Hold the lock switch down and test for continuity to ground. Then take an inline fuse holder with a small fuse, like a 1 or 3, then tap the wire to ground. That will trigger the actuator.
Make sure you're using relays on the alarm wires unless they're high current outputs.