This is what I did.
Object Tab, Background, Surface Shader Tab, I deleted what was there and clicked on the green cross. That led me to Create Shader, Surface Shader, Default Shader. Then click on the green cross to go to Default Shader.
Under the Color Tab there, load your image in the Color Image slot. Then go back and select the Images Tab. Choose the Projection Camera slot, click on the green cross. Assign Camera, Render Camera.
Of course you have already disabled the Atmosphere, right?
I am sure this is not the right way to do this, but it worked for me. :-) Hope I didn't leave anything out.