My network configuration is a little unusual, I suppose. My new ISP gives me a dynamic IP address on the WAN interface using PPPoE, but also routes a /29 to me. Hurricane Electric tunnels are simpler/easier with a static client-side endpoint. What I'd like to do is assign an IP address from the /29 to the router, and tell the IPv6 configuration to use that address, not the WAN address, as its local endpoint.
However, I'm not sure how to do this or where Tomato actually keeps the IPv6 configuration.