Email quota support

[AcE_IoXx]

Hello,

I need quota support for the email accounts, in my VHCS2 i had it working, but in ISPCP i can't get it working.
So what i need is:
a default quota when adding a new mail user
a function in the ISPCP admin page to change the quota
a plugin for squirrelmail to show the usage.

I'm hoping someone here can help me setting this up.

Greetings Christ

PS. I didn't exactly know where to place this post, so please move it if it's in the wrong forum.


PS2
Here is why, my users give away email addresses. But those accounts should have limited disk space. e.g. 20MB or 100MB or whatever (standard mail size should be setup by reseller, and the box size should be changeable by the reseller on request from the domain owner).
This way, one users mail usage isn't affecting the other users.