An official certificate won't solve the problem. You can try the following patch for envir.c. At line 230, change the code block
#ifdef HAVE_SSL
if (session->binding->use_ssl) {
add_to_environment(fcgi_buffer, "HTTP_SCHEME", "https");
} else
#endif
add_to_environment(fcgi_buffer, "HTTP_SCHEME", "http");
to
#ifdef HAVE_SSL
if (session->binding->use_ssl) {
add_to_environment(fcgi_buffer, "HTTP_SCHEME", "https");
add_to_environment(fcgi_buffer, "HTTPS", "on");
} else {
#endif
add_to_environment(fcgi_buffer, "HTTP_SCHEME", "http");
#ifdef HAVE_SSL
add_to_environment(fcgi_buffer, "HTTPS", "off");
}
#endif
Looks like Joomla (just like all other CMSes) is using the Apache CGI standard instead of the official CGI standard.
I know my e-mail address is 'unprotected'. But posting it at this website won't cause more spam. The address is already known by too many spam idiots. And besides that, my spamfilter is working just fine