Question : What does adding an SSL certificate to SMTP protocal do to regular Outlook senders?

I have been trying to get an iPhone correctly configured to send and receive emails through my corporate exchange server.  I have SSL setup with IMAP4 Virtual Server and the correct port allowed on my SonicWall.  I am able to receive and read emails on my iPhone fine with this setup.  I can send an email from the iPhone if SSL is turned off, but I do not want to keep it that way for obvious reasons.  If I add the certificate for SMTP, what will happen to the users that send emails regularly without the iPhone?  Anything?  Does all email have to be then routed through port 465 instead of 25?  Lastly, are their any specific checkboxes I would have to check to require SSL in SMTP?  Or is just simply adding the certificate enough?

Thanks ahead of time.

Answer : What does adding an SSL certificate to SMTP protocal do to regular Outlook senders?

If you  check "Require secure channel" checkbox then the server will require SSL in SMTP and users who send email regularly will fail. If you don't select this checkbox your server will support both regular and SSL clients.