The API is not yet public! They cant release the app in WindowsPhone store until they release the API to public. These developers got the API in Live Lockscreen BETA. only Rudy got the API from Microsoft so only he can release lockscreen apps till they make it public
Yes, i know that, but that app, is a hack, basically custom wp system replaces the content of a legit app(like the live lockscreen) with a custom one, which allows the custom app to access the privileges of the legit app, and that app(custom wp system) supports the live lockscreen app, so you can deploy it on any developer unlocked lumia, even if the apis are not public