Why has it been stated (someplace?) that the sims won't reproduce stall conditions?
You can determine the aerodynamic behaviour also through calculations and wind tunnel testing (which is BTW also all you've got up to the point of the first flight of a new aircraft, and they usually do pretty well out of the box nowadays). So the sim will of course do stall conditions (the other question being how much effort has at all been put into getting the model right for conditions that far out of the envelope), but to know how accurately your simulation reflects the real thing you need validation data from test flights and until now there hasn't been much data from free falling A330s to go on...