Transparent SkySphere

I am trying to place geometry in my skysphere.

The goal is to create an alien world scene. With planets visible in the sky sphere.

The problem I have is that the clouds that are part of the default skysphere always appear behind my geometry. Ruining the illusion

The solution I devised was to create 2 skyspheres. 1 inside the other. Attempting to keep the clouds and atmospheric fog from the inner skysphere and the sky itself to be created on the outer sky sphere. However, I can not seem to make the inner skysphere transparent to complete the illusion.

Any help?