I still can't get transparent https proxy working: HTTPS works only if I
explicitly configure browsers to point to the proxy server. When
accessing a site using HTTPS, the browsers complain that the site
contains no data if proxy setting is removed.

I've used NWADMN32 to turn on transparent HTTP proxy and add 443 port to
it... I've also add [TransparentHTTPS] to proxy.cfg and reload the server
and still no luck. Please suggest some methods to troubleshoot the
problem...