Fumefx render passes?

Hi all,
I am trying to seperate my fumefx scene into render elements.
I need to make my fumefx explosion "Invisible to cam" but have the reflections, shadows and lighting (from the blast) all to remain on the objects around the scene.

Normally, I would uncheck "Visible to cam" on any object's properties, but when i try it with fumefx, I get a soft defused, weird look.

I posted an example of it on this site:
http://forums.autodesk.com/t5/3ds-Ma...4780885#M91356

Does anyone have a work around to make Fumefx fire invisible YET it's reflections & shadows...Visible?
Thanks