This is more of a feature request than a problem. I have recently enabled IPv6 on my network and would like to enable IPv6 on my NAS, and I realize that there are no configuration options to do this right now. Even if it just was a stateless configuration client, and I was unable to manually set the IPv6 address, I would be happy.
Samba has fully supported supported IPv6 since v3.2 ( link here.)
For those of you more curious about IPv6, and how to get it on your home router or PC, please visit http://www.tunnelbroker.net/ for free IPv6 connectivity. Visit their forums for help with setting it up.
Also this is a wiki page about IPv6: http://ipv6wiki.net/wiki/Main_Page
Thanks very much!