Can you give us a sanatized (Remove any passwords etc) copy of what steps your taking to acomplish this? WIthout defining what address' you try to set I cant verify why you would see this problem from linux.
If youd like to start a new thread or just followup in this one with your config id be happy to look into it.
Well I thought I would give a small go at breaking the /64 up into /80's so that I could use one part for LAN and one for VPN on my little home network. But as soon as I did that, my linux box started complaining...
Feb 12 00:25:29 atlantis IPv6 addrconf: prefix with wrong length 80
I could not find any info as to why it would be doing that...
(BTW using a cisco router as the endpoint of which found bridging and ipv6 are not friends...)