the ir coords aren't at a 3d space... they point to a spot on the 2d plane of the screen.  Now, the camera can tell how far it is from the screen, hence you get a z type coordinate, but as far as plotting the ir in 3d space, you would not know where it was in the plane of the screen (depth)

picture a laser pointer shooting into the screen... the "pointer" would be anywhere on that laser all the way to infinite.

Now you could set the "depth" by defining the "laser" at a specific length... ie the pointer is always fixed to the end of a stick on the wiimote... push the wiimote closer to the screen and the pointer goes deeper into the image, pull it back and it gets closer to the screen.  but you would just need to alter the distance from the screen variable and to some math to make it sit where you wanted it in space.

sweet, yeah that's what i would do as well...

Now i see what you were saying about the pointer leaving when you rotate camera.

when you shift the camera's orientation you would have to also shift the "base" of the pointer by that much also.. plus do some trig to adjust the pointers position in space (because what was x and y on the ir corrds is now z and y when you shift 90 degrees on the camera viewpoint)  that's why you lose site of it.