Nick,
1. SAV v8.0 is extreamly outdated. The current release of SAV is 10.x/11.x. SAV does not have any function that can be used to scan mail that is processed by the Mail Server. But once it is saved to the servers local hard drive, the Real Time Protection (Auto Protect) will usually snatch up any infected messages. But I reccomend that you exclude .tmp and the mail server outbox from Auto Protect. If it detects an infected message it will basically pull it out from under ArGo and could cause it to crash.
2. a MX record is placed at your DNS server (the provider who is providing the name resolution for your IP address). If you do not have a DNS server, I can suggest TZO.
3. Archie is a He, not a she :0