tor privoxy squid

[gabrix]

I have installed squid on the gateway machine together with privoxy-tor 
.Squid is configured to have privoxy-tor as parent proxy. Iptables is 
set to redirect port 80 traffic to squid's port 3128 .I have tor-privoxy 
on each lan machine and browsers' torbutton , too.when i start a browser 
connections from a lan machine browsers are configured with the local 
privoxy-tor and with tcpdump on the gateway machine , http traffic 
doesn't seem to go to port 80 where iptables is supposed to redirect 
packets to squid 3128.
If i click on a port 80 url , because tor , traffic goes to tor network 
, let's say 9001 but it differs from time to time.How can i catch with 
iptables tor traffic coming from my lan?By port we sayd too generic, i 
tryied by --uid-owner debian-tor but it doesn' seem to work,neither!
Thank you !!!
My lan machines are debian sarge stable kernel 2.6 , my gateway machine 
is a debian etch 2.6,too.