I find it fairly interesting that most, if not all, of the heavy duty Metro style apps that Microsoft shipped with the developer preview all cheated in scenarios like this. Examples include the "Remote Desktop" metro style app being allowed to load
the RDP ActiveX control, the Control Panel application having a "More settings" option that launches it in Desktop mode, and Internet Explorer having a "Launch in Desktop Mode" option which sure seems to do more than just ShellExecute the URL (which from what
I understand is all Metro style apps are allowed to do).
I understand that this is the new policy of Microsoft but if Microsoft is at times not able to follow their own rules and still provide a full application experience, then perhaps the rules are too stringent?