Flex + AIR on Android - launch install intent with navigateToURL

I have an Android application built in Flex. It is NOT distributed via the Google Play store but just distributed and installed manually.

Now I would love to be able to update the App automatically from our own server.

It should be not a problem to check for the versions and download the file to the Android tablet. But then how do I install the new downloaded version ?

I have found an ANE code snippet that would do just that: Android Air Native Extension to install new apk version throws "no activity found to handle intent"

BUT apparently you can launch these Android "Intents" with navigateToURL directly from Flex: http://ift.tt/1AlHis3

However, I can't find any specifications for that. Any ideas on how do I construct such an URL for the install prompt ?

Before I mess with ANEs maybe someone can point me to an easier solution ?

Thank you very much for your time !