Here folks install this app and use his method/it's the same proxy as above but with a small added step, see: [check out]
When you finally get INSTALL showing click install and then quickly go back and set Wi-Fi back to default otherwise the app may/will stall and
needs attention tap won't work. You can install most of the apps in
purple just don't install any under
WP SYSTEM, they won't work.
nokiaupdates | Windows Phone Apps+Games Store (United States)
I just realized that HTC owners might not be able to download this so...[check out] is after you find the Nokia app that you want in the store send it to your phone via email then set Wi-Fi proxy as suggested above then open that link and when it says "this app not available for your phone" hit the back button and pause 3 seconds and click it again and it should say
install you might have to do this several times but it should work, I've installed several HTC and Samsung app on my Nokia Lumia this way.