IE 11 proxy PAC configuration file

Hello,

I would like to use PAC file to configure my Internet Explorer 11, but so far I'm not able to do so. Below you can find configuration of the Internet Explorer 'Connections\LAN Settings' section and PAC file content (simplified at this moment):

[Unchecked] Automatically detect settings
[Checked] Use automatic configuration script
Address: file://d:/Settings/Proxy.pac
[Unchecked] Use a proxy server for a LAN
[Unchecked - grayed out] Bypass proxy server for local addresses

Content of PAC file is following:

function FindProxyForURL(url, host)
{
     return "PROXY proxy.companyname:8080";
}

Thanks for your help!

Regards,
Stanislav