I was able to test drive a G 3 in my environment. I clicked on the wireless settings and added the SSID and the key. I then held the wifi entry and was able to get advanced settings.
Password: blank we don't need one.
Proxy settings: set to manual
Proxy host name: I put in my proxy.pac address
Bypass proxy for: blank
The "save" button would not allow me to save. Even if i populated every field.