How to Configure SSL for POP3, IMAP4, and SMTP
You can configure Exchange Server virtual servers to use Secure Sockets Layer (SSL).
To configure SSL for POP3, IMAP4, and SMTP
In Exchange System Manager, right-click the virtual server, and then click Properties.
Click the Access tab, and then click Certificate.
Follow the instructions in the wizard, using the guidelines in online help to request and install the SSL certificate.