It seems that within the 3D camera tracker keyframes are not generated that can be viewed under the null's position settings.
Why should there be? You have a wrong understanding. It's a moving camera in a static 3D scene, not the otehr way around. for attaching the Beam effect you might wanan read this:
When you solve for a camera you only get camera keyframes. You don't get keyframes for the objects in the scene. If objects are moving in the scene then you need to either do planar tracking or point tracking. If a large object moves within a scene you actually need to disregard that movement to get a good camera solution because the 3D tracker is a trying to figure out how the camera moved not how different things in the scene move.
You can successfully achieve the effect you want by using point or planar tracking.
Thanks, Rick. That's sort of what I figured, but you clarified it perfectly.