First off, save and/or print these pictures as I don't know how long I'll host them for ya

These are the best pics I could get with my cellphone, sorry. Also make sure your board looks like this too as hooking into the wrong circuit could let the smoke out of something!
You'll need to take the bulb out of the side of the switch to get it apart. I used a small flat screwdriver for the bulb and the 4 tabs holding the case together.
This is the back of the board, you'll want to add two wires where the switch is on the other side (see 2nd last pic):
Close up. You don't want to get solder connecting the circuit beside them, as you can see they are pretty close. A sharp pencil tip type iron is best, you probably don't need to add solder, just melt it and add the wires:
This is the other side, you can see the switch that is pressed (top right under the yellow led.) It's the two inside connections your making with the new wires under the black middle part of the switch (I marked them roughly with the green dots):
This is the notch you'll need to make in the case for the wires and it shows the bulb installed that you need to take out to get it apart:
Then all you need to do is use a relay (pretty well any will work as it's low current here.) The two new wires would go to pins 30(COM) and 87(N/O), and you'd run the wire from your alarm to 86, and use the correct 12V or ground on 85 depend what the output of the alarm is... You need only a single pulse trigger from the alarm to activate/deactivate the relay.
If you need any more help, let me know.
