[horde] imap configuration howto ?

[Mehmet Fatih Akbulut]

hi all,
i have a fake domain akbulut.com and i can login with squirrelmail to any
account of this domain.
but i've problem with imp :'( always get invalid login.
how do i have to change the following lines to be able to login imp ?
$servers['_prompt'] = array(
    'name' => _("Choose a server:")
);
/* Example configurations: */
$servers['imap'] = array(
    'name' => 'IMAP Server',
    'server' => 'imap.example.com',
    'hordeauth' => false,
    'protocol' => 'imap/notls',
    'port' => 143,
    'maildomain' => 'example.com',
    'smtphost' => 'smtp.example.com',
    'smtpport' => 25,
    'realm' => '',
    'preferred' => '',
);

default domain is akbulut.com and imap runs on 143. and imap works fine.
.
.
a login root at akbulut.com akbulut
a OK LOGIN Ok.
a logout
* BYE Courier-IMAP server shutting down
a OK LOGOUT completed
Connection closed by foreign host.
.
many thanks in advance.
Cheers,
MFA