In a nutshell, you can't. Older versions of Netscape (pre 6 or mozilla)
didn't natively support secure POP.
However, the is a way to still use an older version of Netscape with secure POP. It requires the use of an external program called stunnel. Stunnel basically creates a secure tunnel from port 110 (the POP port) on your local machine to port 995 (the secure POP port) on r2d2. This must be setup before you try to get your mail. You then tell Netscape that your POP mail server is "localhost" and stunnel forwards your POP requests to the secure POP port on r2d2. Setting up stunnel varies between machines and OS versions. It is discussed in the previous document. The follow assumes you have already setup stunnel.
First you must tell Netscape that your POP mail server is now your local machine, "localhost". Select "Edit->Preferences..." from the drop down menu and then select "Mail Servers" under "Mail & Newsgroups". Select your current incoming mail server (probably r2d2) and click the Edit button. Change your server name to "localhost" and you should be all set.
This completes the procedure. You should now be able to securely check your email on r2d2.
Note: Please pay heed to the warning when
installing stunnel. You must set the local end of the tunnel to "localhost:110"
and not just "110" or else you'll expose port 110 from your machine to
the world.