Configure Mac Mail for First Class E-Mail? Help!

So I have been able to get Mac Mail on my new MBP to retrieve and send e-mail from three of my four accounts; the one that I cannot get to work is with my mail from First Class, our college's mail server.

I have worked with our IT guy and have all the settings correct in the account creation wizard. Mail connects, populates an inbox, but when I try to sentd mail, I get any number of errors: smtp failed to connect, etc. Sometimes the server has (ofline) next to it in the rely message.

I have deleted and re-created numerous times, deleted the related keychain, restarted, searched this forum and Googled, and I can't find anything.

I really do not want to use the First Class client. I find it clunky, and I just want to have all my mail in one program.

So is anyone here successfully using Mac Mail to send and receive their First Class e-mail?

Cheers!