it seems that no airliner simulators have a ditching program??

Kind of makes you wonder if the ditch switch has a point. Sully ditched about as gently as it would be possible to do, yet the bulkhead was damaged enough to make closing the outflow valves irrelevant.

The ditching switch is useful! I use it a few times per year!! :O No kidding!

@Cubs2Jets,
Those are not "outflow valves", in the picture you posted, but pressure relief valves on the pressure bulkhead. The (single) outflow valve on an A320 is mounted on the fuselage further fwd, just behind the aft bulkhead of the bulk cargo area. Those two relief valves shown, would in all likelihood have remained closed.
The ditching switch (which was not used) would have closed the two fwd avionics cooling valves as well as the outflow valve.

Personally, I wonder if water rushing in the open outflow vlv during ditching might have had something to do with the damage to the aft pressure bulkhead?

In any case, the aircraft floated because of all the air in the wings. The fuel tanks vent out the bottom, so the air was trapped.

I don't think so. I recall reading somewhere that he hit the water at a considerably higher speed and rate-of-descent than he would have liked, in order to land in a stretch of water clear of bridges and vessels.

No criticism. It was a great job, and touching a bridge or ship would have changed the story completely.