how to set up horde imp to use external MTA for sending mails

[shemso]

Hi,
How can I set up Horde IMP to use external MTA server instead of localhost?


/etc/psa-horde/horde/conf.php:

$conf['mailer']['params']['host'] = 'MTAserver.com'; //localhost was here
$conf['mailer']['params']['auth'] = '0';
$conf['mailer']['type'] = 'smtp';

I'm using Centos 3.6 and Plesk 7.5.4