ipfw nat befuddlement

[Randy Bush]

i386 current

kernel has
options         IPFIREWALL
options         IPFIREWALL_VERBOSE
options         IPFIREWALL_VERBOSE_LIMIT=100
options         IPDIVERT
options         IPFIREWALL_NAT          #thanks to paulo and andrey
options         LIBALIAS

# ipfw -q /etc/ipfw.rules
Line 34: unrecognised option [-1] config

# grep -n nat /etc/ipfw.rules
33:add nat 123 all from any to any
34:add nat 123 config if vr0

more clue bat, please

randy