Are you certain that the carbon wheel is for a Ducati? Might it be a 3 spoke off another bike?
I don't have experience of all the single sided Ducati wheels, but all wheels from the 748-998 range should fit the others.
One more thing is that the original wouldn't be magnesium (if it is the original wheel).
You could give Dymag a call, I don't have the number to hand, but I have found them very helpful in the past.
Tim
