Unreal has a quite cool feature. If the server is SSL enabled and the client connects to the SSL port, Unreal allow to oper up using a SSL certificate instead of a password. For this the client provides the certificate and the private key and in the o-line the authentication method is set to SSL, pointing to the appropriate certificate.
When using znc this feature doesn't work any more. I tried with and without SSL connection to znc, using SVN r1672. I guess the client's certificate and key end up on znc and are not transported to the ircd for authentication.
Anyway, thumbs up for this cool bouncer.