How about the old 'let Libero man mark opposition's AMC/playmaker' workaround? That somehow worked in FM11 (just 'worked' however. 'twas ugly to set up), as the biggest problem playing with a Libero was to 'move' him up the pitch and getting him connected to your build-up play. Usually, this guy just sat behind your CBs and didn't do anything at all. Setting your Libero as a guard dog for one of your opponent's central players however threw him right into the action. Though his avg rating suffered massively from man marking, hardly ever got those guys higher than 7.5.
Lack of suitable players who feel at least a litte familiar in SW position is another pain in the ***. Anyone ever re-trained young CBs for playing in SW?
Not many great SW's in the game, Bocchetti and Musachio are the only two that stand out.
Retraining regens is your best bet for getting them in the future, most decent CB regens fit into the role perfectly anyway.