It looks like nobody is supporting auth-conf in XMPP sasl. Well, I don't find it surprising really, since it's pretty much useless as far as I understand (STARTTLS + SASL PLAIN is much simpler), but I'm a bit disappointed, I wanted to look how it would work inside djabberd. Maybe I can get it with GSSAPI mechanism?
(note, auth-conf is just the name of the digest-md5 mode where the confidentiality layer is installed on the connection, effectively crypting the communication between the two parties once the SASL session has been negotiated).