IP alias with exchange server

[adventurehd]

I have a Cisco SA520 and I have a question on sending out e-mail from my exchange box.

I have a couple of public IP addresses and I have set up IP aliases address for both on the WAN port.

When I send out an email, the message is being sent from the public IP address of the gateway instead of the second IP alias I setup to use for my exchange box. How can I configure the router to send out mail from the second IP address I configured and not default to send it out using the gateway IP address?

Thanks.

[adventurehd]

I figured it out myself. I had to specifically add the rule in the firewall for outbound to that port.