Disable loading ipv6 on wheezy NSLU2

[Alan Snelgrove <alansnelgrove@mac.com>]

Hi 

I have lsmod showing

Module                  Size  Used by
ipv6                  262419  18

despite having 
Slug#  cat /etc/modprobe.d/blacklist.conf
blacklist ipv6
and 
Slug#  cat  /etc/sysctl.d/disableipv6.conf
net.ipv6.conf.all.disable_ipv6=1
and 
Slug# sysctl -a | grep disable_ipv6
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1
net.ipv6.conf.eth0.disable_ipv6 = 1

I have read that adding ipv6.disable=1 to the kernel
 line in the bootloader configuration fixes the problem.

But I don't know how to do that on a NSLU2 or anywhere else.

Can someone please point me in the right direction.