Same here. IPv6 tunnel extremity is pinging, but no hist after that.
1059 root@yoko:~/ipv6> ip addr show dev he-ipv6
265: he-ipv6: <POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1460 qdisc noqueue state UNKNOWN
link/sit 192.168.230.3 peer 216.66.84.42
inet6 2001:470:1f12:428::2/64 scope global
valid_lft forever preferred_lft forever
inet6 fe80::c0a8:e603/128 scope link
valid_lft forever preferred_lft forever
1060 root@yoko:~/ipv6> ping6 2001:470:1f12:428::1
PING 2001:470:1f12:428::1(2001:470:1f12:428::1) 56 data bytes
64 bytes from 2001:470:1f12:428::1: icmp_seq=1 ttl=64 time=51.8 ms
64 bytes from 2001:470:1f12:428::1: icmp_seq=2 ttl=64 time=52.1 ms
^C
--- 2001:470:1f12:428::1 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1002ms
rtt min/avg/max/mdev = 51.810/51.984/52.159/0.287 ms
1061 root@yoko:~/ipv6> dig aaaa
www.google.com; <<>> DiG 9.7.3 <<>> aaaa
www.google.com;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 61109
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;www.google.com. IN AAAA
;; ANSWER SECTION:
www.google.com. 300 IN AAAA 2a00:1450:400c:c03::67
;; Query time: 47 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Thu Oct 18 15:11:53 2012
;; MSG SIZE rcvd: 60
1062 root@yoko:~/ipv6> ping6 2a00:1450:400c:c03::67
PING 2a00:1450:400c:c03::67(2a00:1450:400c:c03::67) 56 data bytes
^C
--- 2a00:1450:400c:c03::67 ping statistics ---
5 packets transmitted, 0 received, 100% packet loss, time 4031ms