im pretty sure that someone already figured it out. But anyways, I would like to share what I've noticed with EDGE.

If you're like me, who prefer another application for music playback besides moonshell, you can easily change the center button on the EDGE's main menu to a different application.

All you have to do is put the application in the folder /moonshl and rename your application to moonshell.nds

Now I have lmp on my center button..