Message tone

Does anybody know where to find classical message tone for Ericsson or SE on
the net.
I know that it must be somewhere in my P900 but I don't know where, so if
someone knows plese share that with the rest of us. I want to create a theme
with all the sounds and for messages I want that tone, not any melody. Now I
have to change the message tone every time when changing theme and that's
annoying.

Regards!

Mario