Hi Tony:
Just a few thoughts. Excuse me if these are obvious.
1. Did you restart Apache after making your SSL config changes?
2. Are you really running CENTOS 5.3? Consider updating to 5.9 if you don't want to jump to 6.3.
3. StartSSL certs are supported on most major browsers and operating systems. I think that's what you are asking when you say "globally verified".
4. Did you update your mail config as well as your web config. Often the SSL instructions just tell you how to install the cert for HTTPS.