That is the thing, as far as I can tell (and I have read this on the net as well) when you set up Vue 5 to do an IBL thing with either Global Illumination or Global Radiosity you are stuck with that image pasted on a sphere surrounding your models. You can put a 2d plane or mountain or building or something up to block the IBL image but you can't use skies in the background. You can choose not to have Vue paste the IBL image onto the ground plane but as far as I can tell that is it. If anyone knows differently please let us know.