Imapd Quota

[Eicke Felipe]

Hi folks I have a server 4.8 that runs Postfix 2.0.16
I need to enable IMAP quota to squirrelmail quota plugin.

The imapd informations are the following:
#imtest -a eicke -m login -p imap localhost
C: C01 CAPABILITY
S: * OK [CAPABILITY IMAP4REV1 LOGIN-REFERRALS AUTH=LOGIN]
localhost.xy.com.br IMAP4rev1 2001.315 at Wed, 14 Apr 2004 12:18:06 -0300
(EST)
S: * CAPABILITY IMAP4REV1 IDLE NAMESPACE MAILBOX-REFERRALS SCAN SORT
THREAD=REFERENCES THREAD=ORDEREDSUBJECT MULTIAPPEND LOGIN-REFERRALS
AUTH=LOGIN
S: C01 OK CAPABILITY completed

How can I update my imap server capability to enable quota?
Thanks and regards.
Eicke.