Password History Retention

I want to implement password history on a Linux machine. It would be =
nice to remember up to eight passwords so that users have to use a =
little more creativity in their passwords. A setting for this appears =
to be in /etc/pam.d/system-auth but the authconfig command overwrites =
this when run. How do you convince authconfig to remember and respect =
settings inside this? Or is there a better way to implement password =
history retention?

Thanks,

Brian Simper