I've re-read this thread several times over and am still having a problem.  My SME5.5 server is set to public mode.  My Outlook Express is configured to use port 465.  Certificate was successfully imported.  When I am on the LAN, I am able to make an SSL SMTP connection and send out emails.  Yet, when I tunnel in by dial-up, the server seems to terminate the connection rather hastely.  Regular pop (110) works fine.  The above factors lead me to believe that this is not a certificate issue, but rather server security issue.  Any bright ideas?  The OE error msg is as below.  Any help would be appreciated.
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Your server has unexpectedly terminated the connection. Possible causes for this include server problems, network problems, or a long period of inactivity. Account: 'mail3', Server: 'tango', Protocol: SMTP, Port: 465, Secure(SSL): Yes, Error Number: 0x800CCC0F