Playing with projectors and mirrors

Does anyone have any suggestions for a nice way to simulate the light from a projector bouncing off a mirror, in order to simulate a projector + mirror installation?

Something like visualising the projector cone using a box * VP transform, but reflected in a plane, would be cool. Possible to use the reflect hlsl function with this technique possibly?

(edit) Attached is a file showing the technique to draw the projector light cone. What would be good is to be able to place a plane in view of the cone (drawn by the box), which would then reflect the cone.

(edit edit) Even better would to be able to use projectedtexture.fx (from the slide projector in girlpower) to project a texture to a mesh, but via a reflected plane…

How2ReflectTheCone.v4p (11.5 kB)