I don't know jack about alarms. However I my alarm is intergraded with the door locks. They also lock and unlock with starting and turning off. Is it possible that this is what your "trigger" wire is for?
You know more than me on this subject, (I wouldn't even attempt it) just trin' to be helpful.
2006 Jeep Liberty
Adire Audio 15" Brahma running off Cadence A7hc, Clarion hu, MB Quart 6.5s and 5.25s running off old school Punch 800a4
146+db @ 38hz with 1200w and a single 15"
Lv = [(14630000 x R^2) / (Fb^2 x Vb)] - 1.463R
*Vb = vol. in cu"
**R = sq.rt. A / Pi (for square/slot port)