Also I thought the buttons lit up when there was a notification?
dont think there is a notification light which is a shame as this was something they also missed out on original galaxy s.
there is an app that lights up a pixel on the screen when youve got a notificaton called no led. not tried with sgs2 but used to work on original sgs so should work on this
https://market.android.com/details?id=com.led.notify&feature=search_result