IMAP quota reporting free disk space

Hi,

Is it possible to make IMAP quota commands report free filesystem space? I don't want to set quota limits to individual users, but it would be nice to have an information on the bottom of Thunderbird window about free disk space (it could be percentage of the total disk size).

Anyway I have trouble with quota reporting itself, because I tried to setup a regular quota (100G) first, but somehow Thunderbird doesn't report free quota as it does in case of Gmail accounts.

I added to 20-imap.conf:

protocol imap {
      mail_plugins = $mail_plugins quota imap_quota
}

and to 90-quota.conf:

plugin {
    quota = maildir
    quota_rule = *:storage=100G
}

What else should I add to enable reporting? (without warning emails, commands changing quota and all that stuff)

P.