I don't think you can use exchange natively, but Exchange _has_ a smtp engine.
I'm not too sure why they wouldn't just restrict relaying on the smtp server, and make sure that the server was physically secured from unautherized access.
Just put the exchange server name in instead of the smtp engine. The only real secuiryt issues (at least for standard smtp), is that the smtp server should be configured not to relay. So depending on how they've configured Exchange's smtp server, you may or may not be able to use it.
If relaying is restricted, this means the mail admin will have to allow relaying from the ip of the box you're sending the mail from, say it was 172.16.108.13, for example.
You can test whether it's needed by telnetting on port 25 to the exchange server. Uppercase is what you type:
TELNET EXCHANGE_SERVER_NAME 25
220 exchange_server_name.domain.com Microsoft ESMTP MAIL Service, Version: 6.0.3
790.0 ready at Fri, 2 Apr 2004 18:56:49 -0800
HELO DOMAIN.COM
250 exchange_server_name.domain.com Hello [172.16.108.13]
MAIL FROM: EMAIL_EVENT@DOMAIN.COM
250 2.1.0 emailevent@domain.com....Sender OK
RCPT TO: VALID_USER@DOMAIN.COM
250 2.1.5 valid_user@domain.com
DATA
354 Start mail input; end with <CRLF>.<CRLF>
THIS IS A TEST!
.
250 2.6.0 <EXCH012c7qIA3EEmY000009b9@exchange_server_name.domain.com> Queued mail for delivery
(Note there is a hard return at the end of your data intput.)
When you do your mail from if you get a 250 response, relaying is wide open, and you don't have to worry about getting the mail admin to allow your ip address.
If you get 5.5.0 Relaying denined, then you have to get them to add your IP address to the relaying allowed.
