I just made a new plugin, eBuddyKiller, that recognizes PSM's set by eBuddy and ignores them, using your cached PSM instead. When you log in, it will read your personal message as it is sent by the server and, if eBuddy is detected, it will use your locally cached personal message. It won't affect your contacts' personal messages.
Also, if an eBuddy PSM is detected, it will change any & in your nickname back to &, any < back to < etc, reverting eBuddy's changes.
Fetch it from amsn-extras SVN or download it here: http://www.amsn-project.net/getURL.php?id=244