ipfilter on 6.1

[J.D. Bronson]

Ok guys...now that I have ipfilter working...I need to run a few 
commands in /etc/ppp/ppp;linkup and cant figure out the syntax...


% cat /etc/ppp/ppp.linkup

# It is no longer necessary to re-add the default route here as our
MYADDR:

! sh -c "/sbin/ipnat -CF -f /etc/ipnat.conf"
! sh -c "/sbin/ipf -F -f /etc/ipf.conf"
! sh -c "/sbin/ipf -Fa -f /etc/ipf.conf"
! sh -c "/sbin/ipf -y"

...I also tried with !bg and that failed to.
whats the best way to get these commands to run once my ppp link is up?

thanks-

-JD