WIndows 8.1 Metro Apps ignoring Zscaler proxy Automatic Configuration Script

Currently trialing Windows 8.1. Finding that the Metro Apps are bypassing the proxy automatic configuration script and then getting blocked by the firewall. Symptoms were seeing are the store will load, but none of the icons fill out, another example is Facebook feeds wont update. If we place the machines on a guest wireless which bypasses firewall, all is good.

I've tried the following suggestion but that hasn't made a difference.

netsh

winhttp

import proxy source=ie

I've read about 3rd party apps like fiddler etc to get the Metro apps to run through the proxy, but surely there must be a more cleaner way.

Any ideas?

Thanks

Glen