Sending emails from Vantage through Exchange 2007

Vantage 8.03.407 Progress

We have an Exchange 2007 server. When Vantage sends an email to an
internal email address, it shows up, but the TO address gets chopped
off at the @. It looks like user# with no domain information. My big
problem is that it will not send out emails to any external email
address. I'm not sure if this is a Vantage or Exchange issue. I don't
see where you can define an email login for Vantage, just a from
address and SMTP server name. Any ideas????