Do not double post! If no-one answers your question then nobody knows the answer or you must be more patient.... post reported...
Anyways, if you want to make your own plugin then take a look at the official Messenger Plus! website:
http://www.msgplus.net/help_plugins.php and read the Messenger Plus! API documentation...
Another, not-official, but very good tutorial and examples can be found here:
http://www.geocities.com/raceprouk/msn/plugins.htm
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