Set Proxy

Hi, I need to silently activate Unity 3D on our school PCs. We use a PAC file that blocks the activation process. We also have a manual method which works. I need a reliable way of setting the proxy server address. At the moment I run the below HKCU registry commands which only works 20% of the time.

echo off

reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings" ^ /v ProxyEnable /t REG_DWORD /D 1 /f

reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings" ^ /v ProxyServer /t REG_SZ /d proxy.det.nsw.edu.au:8080 /f

reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings" /v AutoConfigURL /t REG_SZ /d "" /f

I tried the WINHTTP Proxy setting on HKLM but Unity doesn't seem to use this setting.