how to disable ipv6 in freebsd 9

/etc/rc.conf
ipv6_network_interfaces="none"      # Default is auto
ipv6_activate_all_interfaces="NO"   # this is the default
ip6addrctl_enable="NO"              # New way to disable IPv6 support
ip6addrctl_policy="ipv4_prefer"     # Use IPv4 instead of IPv6
ipv6_activate_all_interfaces="NO"   # Do not automatically add IPv6 addresses