Poser 6 doesnt use the IBL image as background as Vue 5 does. To achieve this aim you can 1) take the Probe Light image (as the one shipped with Poser); 2) convert it in a Cubic Environment (Vertical cross) image using HDR Shop (menu: Image>Panorama>Panoramic Transformations) 3) crop the central square of the Vertical cross; 4) use the cropped image as background. I hope I was clear: English is not my language.