Linksys WRT54G V5 problems

I bought a WRT54G Version 4 two weeks ago and it installed fine. Since
then I have been reading about problems with V5, so when my brother
asked for help setting up a wireless network, I told him to try and find
a V4 WRT54G. After 5 stores, he was forced to buy a V5.

Right off the bat, it wouldn't install with the CD, so I tried to
configure it manually. Typing in the config IP only brought up
maintenance mode asking to do a firmware update. 45 minutes later with
tech support and updating the firmware, everything works Ok.

The problem now is when I enter the config utility, I can't find anyway
to setup things like Firewalls, Security etc. All I see is a button to
set things back to default settings. Can someone help me with what I
must be missing.

Thanks
Larry