Oh... well if that's the case, I'm 99.99% sure it won't work. I'm sure Microsoft has an additional layer of security if they themselves are allowing you the option of downloading it on your own on your PC instead of the phone. You can do that with every app on the marketplace, actually.
So I have a dev unlocked phone and, when trying to deploy the file, I get the error "invalid xap". So when trying to "sideload" by putting it on my SD card, I load up the Store and tap SD card and am greeted by seeing the app under a "Unsupported apps and games" section. Something must have detected that the app isn't on the WP8 marketplace (that check is probably made as soon as the file is seen on the card) so it won't work. I also tried the iHeartRadio app, for kicks. Nothing.
Nice try though. Wish it could have worked.