Are you tring to do something like
www1.domain.com -> box1.localdomain
www2.domain.com -> box2.localdomain
With only one external ip? If so, ProxyPass works pretty well. It does seem to be a little slow to me.
If you just want all incoming web traffic to point to an internal box. search for port forwarding on the forums. There are a few thousand threads. There is a port forwarding control panel you can install, though I don't know if it works for 5.5. You can also edit the ipchains rules manually to forward port 80/443/etc to an internal ip.