[imp] IMP User Administration with Dovecot

[IT Engineer]

Hello all,

Hope you are well. I'm using Horde and IMP with Dovecot and things are working
out great ... except for one issue. I'm trying to use the User Administration
application and am getting the following:

  Adding users is disabled.
  =======================
  Your authentication backend does not support adding users. If you wish 
  to use Horde to administer user accounts, you must use a different 
  authentication backend.

Here is my servers.php -- nothing out of the ordinary:

$servers['imap'] = array(
    'name' => 'IMAP Server',
    'server' => 'localhost',
    'hordeauth' => false,
    'protocol' => 'imap/notls',
    'port' => 143,
    'folders' => '',
    'namespace' => '',
    'smtphost' => 'localhost',
    'smtpport' => 25,
    'maildomain' => '',
    'realm' => '',
    'preferred' => '',
);

I have tried adding:

    'admin' => true,

but with no luck. It is even possible to use IMP and Dovecot to add users?

Thanks!

-SG