Billboard particles and RenderToCubeMap

So billboard particles keep themselves pointed at the camera. This seems to break down if you use rendertocubemap. They all just stay pointed in one direction as the rendertocubemap feature spins around collecting each face of the cubemap. Anyone have ideas for how to work around that? I've got a particle effect that is too expensive to render every frame, and I don't need to anyway, I just want to save it to a skybox. This almost works except that the billboards are all out of whack since they are not facing the camera/