Did you try turning the powersteering pulley with the belts on or off? Also am I correct in saying that you are not suppose to try and turn any accessory from their pulley nut if they are still connected to the crank shaft pulley via a belt. You must turn everything from the crank shaft pulley only in the direction of rotation of the engine. Turning it in the opposite direction will damage the engine.
You can watch the pulley turn if you have the engine running or you can remove the double belts on the power steering pump and turn the pulley by hand to check for "free" rotation in either direction. It is impossible to turn these things with the belts on and tensioned. You could easily break off the pulley nut.
Just clarifying wether you tried turning it it with the belt on or off...good luck with your diagnosis.