Network HTTP Proxy Version in Safari

My company recently implemented a new proxy server, however at this point it does not support HTTP 1.1. I know how to configure Firefox and IE, however we have a handful of Mac users here and as the IT guy, I am not well versed enough in using Safari to change the Proxy settings so that it only uses HTTP 1.0.
Safari exhibits the problems of IE and Firefox when they run HTTP 1.1; namely that the page takes a minimum of a full minute to load, if it loads at all. How do I configure Safari?

 

This is not so much about Proxy settings, in IE the option to not use HTTP 1.1 is not included with the proxy settings, it is included in the advanced browser options tab. With Firefox, I have to type about:config in the address bar and look at the advanced options for that browser. How do I get to Safari's advanced configuration for the browser? Not so much for the network settings.