about Gmail and the mail scanner, yes you do have to re-configure your client account settings to non-ssl ports.
e.g. POP 995 >>> 110 (ssl set to none)
IMAP 993 >>> 143 (ssl set to none)
SMTP 587 or 465 >>> 587 (ssl set to none)
once you've done that do a self-test, like send a message to yourself send/receive, then go to the mail shield advanced settings and check the ssl account section. You account must have been detected by the mail shield proxy, and ports should be rerouted there to ssl ports 995/993 and 465. Change 465 to 587/TLS. Both work but TLS is more secure.