Nice try but when you go to Sounds volume your choices are
Ringtones
Music & videos
Alarms
Notifications
There is nothing for System volume which is where you hear the annoying TMobile jingle when you first turn on your phone. I know I just have to live with it (short of rooting), but it would be nice if I could not have it blast the room whenever I would have to turn my phone on (like on a plane after landing, or just my darn bedroom when I'm turning it on for the day).