Sun + background material mode... how do I set it up?

[zeitmeister]

Hey there,
I can't manage to set up sunlight + background material properly.
I assumed that it would be possible to take a HDR image sphere for base lighting, plus a sunlight light source for stronger shadows and highlights.
How do I set it up in the standalone GUI? Thank you very much in advance!

[Zom-B]

Here you go:

[zeitmeister]

Perfect, thank you very very much!!
I put the EXR in the diffuse color slot of the sky material. If you do so, only the indigo sky model is rendering and not the image map.
Thanks again!!