As far as I can tell the only thing Slicksilver managed to accomplish on his server was to remove the ML tag filter and change everyone's font colors. Nice work!
Ephi, I wanted to change everyones colors, and i do have a filter, Just not on. Anyway, If you really want to send a message in chat and your host, type in console:
messageAll(' ',"<Bitmap:Base/(look in base folder for pictures and complete the path)>");
Plus, NiXiLL removed all the filters too. And as they said, Chat filters out bitmaps, So the only way would be to mod your chat like NiXiLL, Clockturn and I did.