Shoutbox

The only thing you need to do, for what you want, is making a script which changes the BINARY registry key:
HKEY_CURRENT_USER\Software\Microsoft\MSNMessenger\FtReceiveFolder

This must be done in an OnEvent_Signin() event (or OnEvent_SigninReady()).
and, if you wish, maybe change it back to what it was in an OnEvent_SignOut() event.

Forget about any script which uses Xniff, that isn't needed at all and will only cause errors and crashes (although you wont notice them).