I played around with this idea for a bit using the Centralite driver on an Iris v2, and using [Release] Nyckelharpa, an HSM Extension. I have a relay to control my garage, so I just need to trigger it to open/close it depending on it's current state.
Using the combination of everything above, I had a rule to set the keypad to armed, and to trigger my relay when disarmed. It would then arm itself from the rule again.
I ultimately wound up abandoning the project though as there wasn't any way I saw to lock the keypad after X failed attempts. This means someone could come by, try out 20 codes, and repeat this until they eventually figured out a working code.
Edit: Correction, i have Iris v3, not n2
