Why isn't IPv6 running on the Home Server from start? That would simplify addressing issues on the local network since Vista machines and the Server could use link local addresses to communicate. I thought all Microsoft apps after Vista would be IPv6 enabled.
Having IPv6 on the server would also help with the NAT traversal for outside access. I'm personally using a IPv6 service called Freenet6 to get a public IPv6 address to the server and this way I don't have to care about configuring the NAT or anything.