Twisted sums, Fenchel-Orlicz spaces and property (M)

We study certain twisted sums of Orlicz spaces with non-trivial type which can be viewed as Fenchel-Orlicz spaces on R-2. We then show that a large class of Fenchel-Orlicz spaces on R-n can be renormed to have property (M). In particular this gives a new construction of the twisted Hilbert space Z(2) and shows it has property (M), after an appropriate renorming.