Squirrelmail plugin

[xtreem]

I've searched high and low with no answers that will help me. I have squirrelmail installed on my plesk 7.5.1 RH 9 system. Squirrelmail is working great. I am attempting to get a quota usage plugin in display the customers available mailbox space. Has anyone gotten this plugin to work on a plesk system? If so what should I be looking for to make this work? Any help would be appreciated.