CAS authentication is available through CasAuthentication and casServerUrl sysprefs.

However, if you plan to use multi-CAS (ie: authentication against multiple CAS server,
you'll have to use C4/Auth_cas_servers.yaml.

Anyway, please keep in mind that if you want to authenticate through https against the
CAS serveur, you have to install Crypt::SSLeay package, or the authentication will 
silently fail.