[Freeswitch-users] making outbound call with IPv6

I'm trying to make an outbound call to an IPv6 host using the pre-supplied internal-ipv6 profile. <action application="bridge" data="sofia/internal-ipv6/nnnn@ipv6-host.domain"/> I can ping the host with ping6, and it has a DNS AAAA record. (There is no A record as the host is a friend's box behind a NAT). My own box is also behind a NAT, but it has IPv6 connectivity via a tunnel broker. The error in the freeswitch.log file is: [ERR] sofia_reg.c:1344 sofia_reg_handle_sip_r_challenge() No Matching gateway found It's quite possible I could be doing something wrong, or there might be a bug somewhere, or the provided internal-ipv6 profile might need some adjusting... Suggestions welcome.