It would seem to me that you would go to the Atmosphere Editor, F4, click the Environment Tab, then Effects, and then, if Vue5 looks like this screen grab, everything you want should be in the left hand column under where you load the image map/HDRI.

 

Once in a while I look around,
I see a sound
and try to write it down
Sometimes they come out very soft
Tinkling light sound
The Sun comes up again