You realise that you posted this 3 times right? I understand your frustration with the difficulties in using CAMduct, it drives me f***ing crazy sometimes (or a lot). But understand that posting multiple times will confuse things if people reply to different threads.

In regards to your fitting, I just noticed that you want the downstream size larger than the upstream. I don't understand why you would need to do this (retrofit?), could you please clarify the purpose of this fitting?

Otherwise, you could shorten the length of the straight piece and add a transition after, not what you want but it will be quite similar.

EDIT - Try CID 1126. This seems to be what you're after.