Making A New Bbcode For Smf 1.09

Im using SMF version 1.09

i would like to make a [mirc] bbcode so that it shows mirc syntax highlighting (as i have an mirc based site)

i have a php script that will do the highlighting, im just really not sure how to incoporate that with the forum.

http://forums.xisto.com/no_longer_exists/ is the link for the script, it is not mine, but made by tye of mirc.net

thanks for the help.

Ive asked on the simple machines forum but theres been absolutely no help, so if anyone here can help me out, id really appreciate it.