He was wanting to use one of the function buttons, the 4 buttons on the left of the keypad to turn of the lights without arming the system.
Oh yes--I get that. Based on his statement that he didn't want to link the two, though, I'm suggesting that you can use detailed arm state to support the all-lights-off function.
I don't use the four buttons for anything, so I can see how that would be useful... however, I just go off of alarm state. Alarm armed AWAY, all lights off. Alarm armed STAY, selected lights off. Alarm disarmed, select lights on.