From what I can determine, the IBL in those P13 scenes is only for Preview and is not intended for Superfly rendering.  The lighting comes from the HDR background which renders very well in Superfly but will give you a black background with Firefly.  The Environment Preview is a projection prop that, I believe, captures the image from the IBL.  That, in conjunction with the light and HDR background, works as a rotatable platform to change the background scene in real-time.  I have the misfortune that one of my computer's onboard graphics cannot handle those scenes very; the IBL lighting is in the wrong x rotation to properly illuminate the Preview and the Material Room setup disagrees with how the arrangement should work.