[horde] ingo uses wrong user for login

[A. Schulze]

Hello,

my ingo installation does not work as expected and I cannot see why :-/

I have full mailaddresses as userid. This address is used by imp and  
ingo to login
into a dovecot imap and dovecot managesieve server.

this is my horde/config/backends.local.php:
<?php
$backends['imap']['disabled'] = true;
$backends['sieve']['disabled'] = false;
$backends['sieve']['transport'][Ingo::RULE_ALL]['params']['hostspec']  
= 'imap.example.org';
$backends['sieve']['transport'][Ingo::RULE_ALL]['params']['usetls'] = true;
$backends['sieve']['script'][Ingo::RULE_ALL]['params']['utf8'] = true;

the imap/manageseive server do log the full mailadress on user login.

On an other Server with the similiar configuration (usetls = false)  
ingo fail to login.
Dovecot log a username without domainpart. But imp uses the full username.

I also enabled some logging in ingo/config/hooks.local.php / transport_auth
I printed out $GLOBALS['registry']->getAuth(null) and there the  
username did contain a domainname.

What did I wrong this time ?
Any hints?

Thanks,
Andreas