[imp] Quota over 2GB

[ssoo@siliconfile.com]

Horde/IMP cannot handle quota over 2GB:
  Under 2GB quota -> Quota status: 45.81MB / 1024.00MB (4.47%)
  Over 2GB quota -> Quota status: NO LIMIT

My environments are:
  Pentium4(32bit), FreeBSD-5.3, Exim-4.60, Courier-IMAP-4.1.0,
  Horde-3.1 / IMP(H3)-4.1

horde/imp/config/servers.php:
$servers['imap'] = array(
     ...
     'quota' => array(
         'driver' => 'courier',
         'params' => '',
     ),
);

Exim-4.60 can handle quota over 2GB.
I don't know couier-imap and horde/imp can handle it.