OK.. I got it to work.. Even got it to send to gmail.
The first entry in the SMTP sender is dedicated to exchange information between multiple VM Pro servers. Set the SMTP Receiver tab to Internal with some internal IP address, I used our CCR Server/SMTP Relay Server (which SMTP Relay is not required, but does work. But that's another subject)
The rest of the entries in the SMTP Sender tab are for SMTP servers where you're users have email addresses. Example: If you have a user at gmail.com then you will need an SMTP entry for gmail. If you have another user at avaya.com, then you will need an smtp server that accepts messages for avaya.com.
As for gmail, or companies that use Google Apps for Business, you will need to setup an smtp sender to: aspmx.l.google.com port 25. This smtp will validate the recipient and allow the message, but will deny all others.
So, in summary, the first entry is used to exchange information between vm pro servers, and you MUST have an SMTP Sender entry for each seperate SMTP server that is required for your users. The match is defined by the domain name of the user. If you have user@abc.com and user@xyz.com that both use Google Apps for Business, you will need two SMTP sender entries. One for abc.com to use aspmx.l.google.com (port 25) and then a seperate entry for xyz.com to use aspmx.l.google.com (port 25).
Now this application does NOT support TLS. So any SMTP server you use as a SMTP Sender must support non-TLS email recipients. Example, I had a test email on a domain (names changed to protect the innocent), Testuser-AT-mydomain.com, and I can send messages using the username and password of that account, then I can allow that to relay messages for me. Just make sure it's using port 25.
If you want to look into a way to relay an SSL/TLS email, have a look here:
They talk about using a program called STunnel that will convert a NON-SSL email to good SSL email. I didn't try this, but maybe something to look into.
I know this is long winded, but it took me 2 weeks of troubleshooting, one public IP SPAM-watch I had to get removed, and a whole lot of late nights to get this information.
I hope this helps.
--DB
Remote Support Specialist