Thanks for the reply.
Well how come you can get programs that hide the icon(s) of program(s) in the system tray? Aswell as hide the process in the Task Manager? Surely there is a way to do this, even if it's not in JScript. Like you said a DLL...here's a link to a similar plug-in for normal Messenger Plus!
http://360software.dakotabcn.net/umlock/index.html
This would allow you to hide msn's system tray icon with a shortcut.
I haven't given up yet because I know software can do this like...
the ones at this page