Okay, I have a little problem here. I have LDD Extended, and I want to put on a Driving Ring (http://www.peeron.com/inv/parts/6539) to a "Cross Axle, Extension, 2m" or "Technic Axle Joiner Inline Smooth" (http://www.peeron.com/inv/parts/6538c) but it won't :( any help please! :)