Can't mute notification sounds temporarily when they go off.

[tr1ptheory97]

Hey guys, I just upgraded from the Epic 4g to the epic 4g touch. Now my problem is, that when I get a text or whatever other notification I can't simply mute it via pressing the power or volume button like its predecessor. I have to unlock the phone and actually click the message or notification so it stops ringing. Is there an option or something that I can enable for this? It's quite annoying.