I have flown CJ's and Phenoms single pilot and as far as I am aware, EASA do not recognise a multi-pilot rating for either of those aircraft. I had a short discussion with the UK CAA when I first had the CJ rating and the way that the single pilot vs multi pilot flying of those aircraft was being controlled was via the IR. During the rating or the renewal you were issued a single pilot or multi pilot IR and that allowed you to operate the aircraft in the appropriate capacity.
Just an observation, if I'm wrong, sorry...
cheers all
By the way Marty, you are allowed to fly your fighter because you are expendable... I, on the other hand, am not.