[Zope] How to accaess ssl related CGI environment variables

Hello, I'm trying to access ssl related cgi variables (like SSL_CLIENT_S_DN) in zope without success. I use apache/mod_ssl with client certificates and accessing zope with pcgi. Apache verifies the certificate, but how to know it in zope? REQUEST.eviron only have a HTTPS key. I'd like to authenticate based on the SSL_CLIENT_S_DN. Any suggestion? Istvan Vago