6to4 WAN config not returning default gateway

[lohphat]

Using 6to4 on Verizon FiOS. I have to force a static IPv6 address for the gateway as the WAN interface doesn't seem to figure it out when the tunnel is created:

IPv6 Address (obfuscated)
2002:60fa:xxxx::
Subnet mask IPv6
16
Gateway IPv6 (obfuscated too)
2002:c058:yyyy::

I have to manually force the monitor gateway to 2002:c058:yyyy::1 for gateway monitoring to work.