Specifying an IPv6 suffix

[Robert Moskowitz <rgm htt-consult com>]

I want to control the IPv6 suffix for my interfaces and let the prefix
be set with RA.

Currently I can either have the RA prefix with the MAC address for the
suffix, or I can specify a complete IPv6 address (and gateway) and
ignore RA (doing this manually in the ifcfg-eth0 file as I don't see how
to do this with Network manager).

The first approach causes problems with DNS if I change the interface.

The second approach causes problems if I change the network prefix.

Or I could implement DHCPv6, but would still have to change its content
if I change the MAC address.  And I don't want to ge the DHCPv6 approach
anyway.

The way I want would be better:)  but I don't see that it is supported.
My current systems are Centos 5.5 and FC12, so I am stuck, probably with
the world as it is, but at least with FC14, it would be nice....