prerouting packet on same computer

[Willy K. Hamra]

hi, i want to forward packets going to port 80 into 3128, using iptables.
the only problem is, this prerouting, while easy to achive if i'm
forwarding the packets COMING to port, is hell for packets going to port 80.
the only command i see all over the web is:
iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT
--to-port 3128
this doesn't work if the packets are originating from this computer.
anyone good with iptables who can help?
thanks
-- 
Willy K. Hamra
Manager of Hamra Information Systems
Co. Manager of Zeina Computer & Billy Net
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