2003 malibu unlock problem

Hi,  I just replaced a remote starter/alarm in a 2003 Malibu.  One problem I am having with both units(old and new) that were installed is that if the vehicle sits for about 20 mins or longer, when I go to unlock the doors with the remote, the alarm will disarm but the doors will not unlock.  I have to either lock/arm the car first or start the car with the remote as if to wake it up before I can hit the unlock button to actually unlock the doors.

Also I am using the dome light as the door trigger and I usually have to wait 10+ seconds till the dome light turns off until I can arm the car properly, is there a better trigger to be using? 

Does anyone have any suggestions to fix the problems/annoyances??

Thanks

It is a 2003 CLASSIC.  The epsilon came out in 2004, so that model year you had both options available.

Thanks

I just tried the double pulse to unlock, let the car sit over 20 minutes and nothing.  I have to hit the lock button, re-lock the doors, then I can use the unlock and it will unlock the doors but now with a double pulse. 

Any other thoughts??

 the alarm will have a wire that will turn on domelight upon unlock(dome light supervision)use this to send a neg to the white domelight wire.

i assume whoever did the original install put a resistor on the unlock? generally on cars that go to sleep, pulsing a door trigg or domelight will wake them up.