I purchased a 70-200 VR Nikkor ED lens last year. Since then, I have purchased both the 1.4 and 2x teleconverters for this lense. (They are the 14eII and 20eII teleconverters.) I want to "stack" them to achieve the greatest possible magnification. But, they do not seem to fit. Am I missing a part? I only did this because I am sure that John Shaw described this process at a seminar. Can anyone help me?