[horde] How to enable Quota function ( status ) for user ?

[edwardspl at ita.org.mo]

Dear All,

Mine is Linux FC6 and Dovecot ( Mail Server : pop3 and imap )...
So, how to config the following setting for user reference ?

imp/config/servers.php :

'quota' => array(
'driver' => 'false',
'params' => array(),
),

Thanks !

Edward.