I am totally new with Kamailio but i have needs to build small cluster of Asterisk. Right now I could succesfully register to asterisk via kamailio and even make a call to hear tt-weasels but Asterisk cant close call

My infrastructure diagram is here http://www.asciidraw.com/#Draw6816041626716434245/903175935

This is what probably I need is to know how to tell to Asterisk that send BYE to private IP of Kamailio instead public IP of Kamailio, am I right ?