On reflections... Well the object, perhaps a square or "plane" object, behind the camera should work wonderfully. The trick is to turn shadows OFF for this object. You do this inside of the material editor, see the picture. This should turn off any shadow-casting. WHY it's right here, I don't know, it just is! When you're playing with volumetric clouds sometimes it helps to turn off Cast Shadows for preview rendering, especially. Hope this helps? Another way to do it is to use the same technque, but wrap your texture around the inside of a sphere, enclosing most of the scene but invisible anywhere else in the render...