DNS and IPv6 environment

I'm testing an IPv6 environment.
Server1: IPv4 and IPv6, DNS and DHCP.
Configured to listen for DNS on IPv6 -> dnscmd /config
/enableipv6 1
Added the IPv6 addresses -> netsh interface ipv6 add address
"Local Area Connection" [IPv6 address as below]
FEC0:0:0:FFFF::1
FEC0:0:0:FFFF::2
FEC0:0:0:FFFF::3
Server2: IPv4 and IPv6, IIS, DNS server Ipv6 addresses set to Server1
Server3: IPv4 and IPv6, IIS, DNS server Ipv6 addresses set to Server1

With both IPv4 andIPv6 installed on all servers, I can ping and resolve Ipv4
and IPv6 addresses.
I'm trying to set up a pure IPv6 environment. It seems I must have IPv4
protocol enabled on Server1 or DNS service doesn't start. Once I remove IPv4
on Server2 or Server3, I can no longer resolve names using DNS. Network
analyzer Ethereal does not show any connection using the IPv6 protocol for
DNS.
Is it possible to have all three servers using only IPv6? Am I missing some
configuration settings for DNS using IPv6?