Hello,
on CentOS 5 with Dovecot 1.0.5 and Horde 3.1.4 / IMP 4.1.4, I have this
configuration in the file horde/imp/config/servers.php
$servers['imap'] = array(
'name' => 'IMAP Server',
'server' => 'localhost',
'smtphost' => 'my.smtp.host',
'hordeauth' => true,
'protocol' => 'imap/notls',
'port' => 143,
'maildomain' => 'my.domain',
'realm' => '',
'preferred' => 'true',
'quota' => array('driver'=>'courier'),
);
the courier driver is used to display users's quotas
Good luck (and sorry for my english)
Yannick