@jimb OK, i'm done. thank you for help 
I found following commands are important if using ip6tunnel in a pptp
echo "1 admin" >> /etc/iproute2/rt_tables
ip route add default dev ppp0 table admin
ip rule add from your_ip_from_he table admin
and BTW, when creating the tunnel, use
ip tunnel add he-ipv6 mode sit remote X.X.X.X local Y.Y.Y.Y ttl 255 dev ppp0
BTW, thank mthode, he's the one that did that howto.
Those commands you talk about are to set up a policy route. This is needed for Linux because the both the PPTP server and the 6in4 server have the same IPv4 address. Since routing normally only pays attention to destination addresses, and because the PPTP software puts a host route into the main routing table for the HE server so that the PPTP traffic doesn't try to use the ppp0 interface itself, a "special case" route is put in so that when the source IPv4 matches the PPTP assigned IP, it uses a different routing tabled (called "admin" in this case), which has the default route pointing through the ppp0 interface. This way, "normal" traffic uses your standard default route, and traffic originating from the PPTP IPv4 (such as your 6in4 tunnel's traffic) takes the PPTP tunnel.
Yeh. Always a good idea to specify the device when you're setting up the 6in4 tunnel. I don't
think it's required, but I wouldn't trust it to guess the right interface.
