How to enable IPv6 on a subset of interfaces

[Brett Lee]

Hello,

Using FreeBSD 8.0-RELEASE, and am trying variations in /etc/rc.conf in 
an attempt to enable IPv6 on ONLY one of the systems two interfaces.

Specifically, em0 should be enabled IPv4 DHCP, and bge0 should be 
enabled IPv6 only.

 From the KAME link below, and the files /etc/network.subr and 
/etc/defaults/rc.conf, am reading that "ipv6_network_interface" should 
work; however the following still results in em0 obtaining IPv6 addresses:

http://www.kame.net/~suz/freebsd-ipv6-config-guide.txt

ifconfig_em0="DHCP"
ipv6_enable="YES"
ipv6_network_interface="bge0"
ipv6_network_interfaces="bge0"

In another attempt (see link below), it looks like "ifconfig_em0" may 
support a "NOIPV6" param, but in practice it doesn't seem to work for me:

http://lists.freebsd.org/pipermail/freebsd-rc/2007-May/001106.html

ifconfig_em0="DHCP NOIPV6"
ipv6_enable="YES"
#ipv6_network_interface="bge0"
#ipv6_network_interfaces="bge0"

Am hopeful that someone might point out how I could enable this 
configuration.

Thanks in advance!  -Brett