I've not got FM loaded up just now so i cant take printscreens just now, but i'll give you a basic run down of my formation. Im playing pretty much the same formation as you, except with wingbacks instead of full backs, so it becomes a 433, fluid and attacking, short passing, expressive, more pressing, normal tackling, drill crosses, and more roaming.
My first team is: (I'm Man Utd btw)
Gk: De Gea (Sweeper Keeper, defend)
Cb: Vidic (Ball playing defender, stopper)
Cb: Ferdinand (Ball playing defender, covering)
Rwb: Lahm (Wing back, support)
Lwb: Evra (Wing back, support)
Cm: Fletcher (Ball winning mid, support)
Cm: Carrick (Deep lying playmaker, support)
Amr: Hulk (Inside forward, attack)
Amc: Rooney (Attacking mid, support)
Aml: Nani (Inside forward, Attack)
St: Hernandez (Poacher, Attack)
Its not exactly like Barca, it has similar pressing and passing to Barca, but i play slightly faster, and whereas they play with 1 defensive mid and 2 centre mids, i play with 2 centre mids and an attacking mid.