Great explanation!
But a question:
If I'm using an italian version, I have to delete the folder squid not to give error during install the new packages:
rm -rf /usr/share/squid/errors/it*
or not?
I tried to do what you said, but in the home page Endian tell me that Proxy HTTP is On, but (
) in the System information page it tell me that the Web proxy is stopped and I can't restart it in anyway...
Any suggestions?