the problem is in the tittle.

I did two tests on Windows 8 RTM :
1) Without the proxy, evrything is going well, I can download apps.
2) With the proxy, all the Metro Apps can reach internet (even the Store or IE), but I cannot install anything from the Store.

Of course I have to use the proxy. My proxy configuration is made by a proxy.pac file in the Internet settings

Do you know where can I configure the proxy use for downloading apps from the Store ?

Thank you in advance !