Olli Heiskanen ohjelmistoarkkitehti@gmail.com:
Thanks for the help, here's what I dug up:
The users are visible in Kamailio, output of kamcmd ul.dump: (here 1.1.1.1 is the public ip of my Kamailio+Asterisk server and 2.2.2.2 is the public ip of my home network)
Looks like problem is not in Kamailio or SIP message flow. At least I can't spot any problems from registration dance or usrloc sample.