Allow my app to be opened with camera button

Question

I'm working on a WP8 app that will utilize the camera for a feature. I've read that, as of GDR2, you can now change which app opens with the camera button , but:

it appears that an app needs to be specially written to be used like this; not every photo or camera app can be configured to launch when you press the Camera button.

Question: What do I need to do in my app for it to become an available option in the "Pressing the camera button opens: " drop down when navigating to Settings -> Applications -> photos + camera?

Additionally , part 2 of this question would be (if part 1 is possible), when the application is launching, can I determine if the user opened it via the camera button (so that I could go straight to my camera feature)?

I've seen this article but it only describes how to use and handle the shutter button, it doesn't mention how to allow this button to open the app .

Has anyone been able to accomplish this?

Answer 1

This thread ( http://forums.wpcentral.com/windows-phone-8/234751-changing-default-camera-app.html ) seems to suggest that only manufacturers can create apps that can do this. Not sure if it's definite, but I've never heard of a 3rd party camera app that can do more than register as a lens .