"To do rear projection it would have to be capable of flipping the image horizontally. I think it's fairly standards, but check what control you have over the image just to be sure.
For example, I've seen projectors mounted upside down from the ceiling with the controls facing downwards project an ""upright"" image - i.e. one rotated 180o."
Generally, projectors have a flip setting to allow them to be used from either side. Most graphics cards also offer this feature for any display output, so even if your projector doesn't support it, your gpu probably will.
