a question about array() in horde.php ..etc

[A. Gehani]

Hi everyone,
This is pretty much my first posting to this list. I would like to use 
Horde and IMP as web-based mail client to our IMAP mail server. 
When configuring Horde, I'm stuck at few lines like:
$conf['auth']['params'] = array();
$conf['category']['params'] = array();

On the first line, I'd like IMP to authenticate users against the IMAP 
server. Is there a guide on how to assign the values in array()? those 
two particular lines lack examples in horde.php.

Thanks a lot.
Ab