ok rawalanche, i will report it too, it is really tedious working without this interactivity! and thanks for the quick answer!
There is also temporary workaround:
1, Create a large sphere around your scene
2, Invert it's normals
3, Create material, instance environment map in it's diffuse slot, enable showing of texture in viewport and apply it to the sphere
4, Open object properties of the sphere, disable "Renderable", "Show frozen in gray" and "Ignore extents"
5, Freeze the sphere...
6, Make sure environment texture mode is still set to spherical environment
7, Now you can adjust your environment rotation and see it in viewport
It is quite painful workaround, but it is better than nothing, until autodesk fixes the problem...