Here's an example of how to setup your layers to get depth on your Z Axis when rotating on your Y Axis.
I was having some trouble getting this to work in a project so I stepped out and started a simple example to try to find the proper way to set this up. It appears as though you need to enable the preserve-3d transform style and make sure that layer does not clip for z-axis depth transforms to work properly.
I worked out the solution and figured I'd share with you all. :D