foward with suseFirewall how to?

Hello! My problem is the next: - I want to foward 192.168.X.Y: Port:80 to 3128 so that Squid can take care of! - 1 Problem i have 2 windows clients should be allawed acess to the internet but only trugh the transparent proxy. after adding this line to Susefirewall2 config file "192. 168.X.Y,0/0,tcp,80,3128" the windows client recives an ansuwer from squid telling that can't find "http://google.com:3128". But if i tell windows that there is a proxy at "192.168.X.Y : 3128" that does not append. João Alvega