After rendering my model I selected "Save Layered Image" assuming it would save different layers that I could manipulate in photoshop... but when I open it all I get is this

which is the ENTIRE THING in one file... then I get this

it says this is the alpha channel.. which is nothing but a white square with a few shadows from the lights at the top..  Why is this happening?... what's SUPPOSE to happen?.. I assumed everything would be saved as an individual layer that I could manipulate in photoshop... or even take a piece to use in another graphic.  Can someone help with this?  Thanks in advance.