Isolating and rendering shadows/reflections on transparent layers

[dedavai]

Hello experts,

 

I'm have a simple scene with an object in it. I want to isolate only the shadows and reflections, and render them into 2 separate images. These images should be fully transparent, except the shadows/reflections and their alpha information.

 

I tried to achieve this by using isolated render elements, but the shadows/reflections are rendered on a black background, and there is no way to separate them from the background. I'm trying to get just the shadow of the object on a transparent PNG/TIFF without any other elements/backgrounds in the image. How is this done?

 

Thanks in advance.