[imp] smtp auth setup

[Gerald Griessner]

I'm trying to get smtp auth with imp working.

I configured horde.php as noted:

$conf['mailer']['type'] = 'smtp';
$conf['mailer']['params']['host'] = 'mailserver';
$conf['mailer']['params']['auth'] = true;

When IMP sends a message to the mailserver tcpdump says following

response from mailserver:
250-mailserver Hello webserver
250-SIZE 7000000
250-PIPELINING
250-AUTH PLAIN
250 HELP

imp sends:
AUTH PLAIN
well, the information about username and password is missing, thats what
exim complains about.
I read through the mailing list archive, but I couldn't get a hint.

My setup:
Horde 2.2.4 stable, IMP   3.2.2 stable
mailserver:  exim

can anybody give me a hint?

is there a chance to get IMP working with STARTTLS?

thx
   Gerald