[SR-Users] SBC and HA with Kamailio

Hello, I'm new with Kamailio and have to do a research project with Kamailio server. My task is to realize a SIP infrastructure with NATing and a High Availability Cluster with two Kamailio server. For the NAT problem I found a solution with SEMS, but for security I need authentication on the SBC. I have no idea to synchronize the user authentication information from Kamailio to SEMS. Perhaps there is a more useful solution available? The SIP server is behind the NAT in a private network and the SBC to be placed in the DMZ. A new feature of Kamailio 4.2 is a replication for High Availability (HA), but I did not found any information about this. Is there somewhere a documentation or howto where I can look? I need only short keywords and not a complete description. Many thanks, Kai