Pop3 Problems

Hi folks!

At the moment I'm evaluating ServiceDesk for my company.
Program works fine except for one thing.

Can anyone please help me out on this thing?

The thing:

I Can't fetch mail from pop3 or imap mailbox.
Mailserver is Exchange 5.5 on a windows 2000 server, both with latest servicepacks applied.
Tried to authenticate using telnet on port 110
But username and password are not accepted in plain tekst.
When using outlook with "secure authentication" enabled the username and password are accepted.

I don't want to lower security settings (defaults) to let servicedesk (and other users/ programs) authenticate in clear text!

How do I set ServiceDesk to secure authentication?

Thanks in advance!