[imp] Purging Deleted Messages

[Ed]

We are using disk quota's on our mail server.  IMP is set to mark the 
messages as deleted rather than move to Trash.  We chose this option 
because when a user is near/at quota, the uw-imap server will not allow the 
"deleted" messages to be moved to the Trash as the users does not have 
enough disk space available.  We are now running into the problem that many 
or our users are not purging his/her deleted messages and as a result are 
reaching his/her quota.

Is there any way that deleted messages could be purged at login or once a 
day (similar to the way the maintenance can empty the trash)?

For now, I changed the 'delhide' pref as listed below to prevent users from 
hiding the deleted messages, but the user still must purge deleted messages.

// hide deleted
// a value of 0 = no, 1 = yes
$_prefs['delhide'] = array(
     'value' => 0,
     'locked' => true,
     'shared' => false,
     'type' => 'implicit'
);

When the 'locked' is set to true, the "Hide Deleted" link is displayed but 
no longer does anything, on the other hand if the value = 1 the "Show 
Deleted" link is displayed but no longer works.  Should these links be 
hidden when the pref is locked?