This happens to me alot in the swedish league, actually what I do (most of the time) when they park the bus, is play defensively and hit them on the break (I also play wide), give them a taste of their own medicine.
Games usually end up 1-0 or 0-0 and occasionally I get a quick one in the beginning of the game and then pile on the pressure, especially if their attackers are slow.
Though my results might be purely due to the lethality of my strikers...
Try fiddling with the time wasting option to try and make players with bad decisions come out to close down you players, might open up some gaps...
That's generally what Barca is doing IRL when facing inferior opposition like real madrid and the likes

They play the ball around in their backline and central mids to make the other team push up their midfield and then cut through it.
Actually I remember seing this alot in FM06 when playing with high time wasting and technical players usually though when trying to kill the game, but it might work, I'm off to try it