Streaming audio playlist default application

[lotech]

Amarok is the default player for .pls files, I added xmms as the default app for it but doesn't work, playlist still opens with Amarok, I removed Amarok but Mplayer opens instead ! how to make xmms the default app for playlist ?

[Husse]

Preferred programs in the Control Center
Also settings in Firefox if you start it through FF