I was going to take some pictures and probe some more and have answered my own question (kind of) I think what I really need to do is change the style of expansion plug for the carbon fork. The current one has a set of threads the cap screws onto and what I need for the ZIPP cap is a expansion plug that accepts a bolt that in turn holds the cap on.

Which leads to a qustion raised from above. If I remove the existing expansion plug do I need to pre-load the headset to put in the new expansion plug? If so how.