Strangely enough I have my display to sleep for after 30 seconds, backlighting on auto, and the touch buttons stay on in a dimly lit room. However, if the lighting conditions are, well, umm, bright... the touch button LEDs turn off. If I leave the phone alone (30 seconds for the screen sleep) and then dim the lights, the touch lights turn on. UGH!
Oh well. It's almost too bright for me to sleep with on, anyway. I ended up turning the display off last night. :/