send emails with mailgate, but not Exchange

[gabriellai]

Hi all,

I have a Linux system running a antivirus scanner, call it Mailgate. This system will receive emails from the internet, then will forward to MS Exchange Server. But when client wants to send emails, emails must be scan by Mailgate before sending out to the internet.

In Exchange Server, how can I do that?? How to configure so that emails from incoming & outgoing will be deliver.

Please advice