integrating house alarm


I have a standalone gsm house alarm and would like to arm and disarm remotely and also when I arm the system it activates a scene

how I foresee it working is

1: hook up 2 zwave relays to arm and disarm the alarm(unique arm and disarm buttons) by hotwiring the remote, but what plugin to use? if I use a garage door plugin for a 2 second on off, the garage door sensor that is required for the plugin… what and how to take care of that?

2: arm alarm from panel or remote, siren chirps and that chirp initiates a scene in the controller to power off certain lights ect