[Serusers] failed INVITE using IPv6

Hi I'm trying to use sip-communicator with ser over IPv6. Using IPv4, everything works fine. With IPv6, users can register at the SIP server, but INVITE fails with the messages below. The o-uri=sip:127.0.0.1:5060 looks like the source of error to me, I'd expect an IPv6 address there. Any ideas? Regards, Martin 0(46056) ERROR: udp_send: sendto(sock,0x282ff758,842,0,0x282fde90,16): Invalid argument(22) 0(46056) CRITICAL: invalid sendtoparameters one possible reason is the server is bound to localhost and attempts to send to the net 0(46056) msg_send: ERROR: udp_send failed 0(46056) ERROR: t_forward_nonack: sending request failed 0(46056) ERROR: udp_send: sendto(sock,0x282ffab8,846,0,0x282fdf70,16): Invalid argument(22) 0(46056) CRITICAL: invalid sendtoparameters one possible reason is the server is bound to localhost and attempts to send to the net 0(46056) msg_send: ERROR: udp_send failed 0(46056) ERROR: t_forward_nonack: sending request failed 0(46056) ACC: transaction answered: method=INVITE, i-uri=sip:martin@sipgate.ctlabs.ch, o-uri=sip:127.0.0.1:5060;transport=udp, call_id=eff5eafae8208c8f2ad61c67dbcdf368@[2001:918:ffff:1000:48c4:4495:3 c73:dd3a], from="Sean" <sip:sean@sipgate.ctlabs.ch:5060;transport=udp>;tag=26530674, code=477 # serctl ps 0 46045 stand-alone receiver @ 2001:918:ffff:1000:210:b5ff:fe4f:25d8:5060 1 46046 timer 2 46047 fifo server 3 0 4 0 5 0 6 0 7 0 8 0 9 0 10 0 11 0