of course Ipv6 traffic is routed via internet and not via tunnel, assuming you use the delegated public prefix. IPv6 normally uses globally routed Adresses. You'd have to assign a local IPv6 prefix to a network connected via red (i dont think split mode would work) and route everything through it, than do masquerading on the IPv6 Subnet behind the RED -OR- have a /64 (from the provider) assigned to the RED network, activate prefix advertisment or DHCPv6 on that Interface.
