I think you're saying that the current camera is looking through glass, and that may reflect the IR beam.
Consider eliminating the glass, and replace it with some type of plastic that you can drill/cut. Then buy a round camera with IR lights that mounts in a round hole. Now your camera will not reflect off the glass.
I did this on my Endeavor, and added a second camera on top of the original camera housing (which was about 4 inches wide), and use the second camera for a more distant view of the lanes behind the motorhome.
I have a word document describing my installation with some pictures. If you want a copy, send me your email address via PM.
I agree with the comment about using a CCD type camera, which is what I have for the rear view. I'm using cheaper CMOS cameras for side view, and there is a difference. I think the CMOS works fine for side view but I like the CCD type for the rear view.
Fred