We just made the discovery (ok, it's likely old news to Microsofties, but I've been blessed I guess) that Outlook's Test My Settings button only appears to show up if you're using a POP account - not IMAP.
But that's ok, because it returns false results; it says things fail when they don't, at least if you're using SSL on not-port-25.
The mind boggles. "Don't use open source, it's poorly documented and doesn't work right." Yeah, right.