Alex, I made tpoxy work with freebsd work about 2 years ago but that will not help you as my memory is rustic on this subject. Trick was to create firewall rules to trap on port 80. then force caching thru squid with diverts. Change squid port from 8080 to 80. I think best way is to run a port log on firewall and see where the packets are going. HTHs.