I believe this is the official rule.
A pitcher must indicate visually to the umpire-in-chief, the batter and any runners the hand with which he intends to pitch, which may be done by wearing his glove on the other hand while touching the pitcher's plate. The pitcher is not permitted to pitch with the other hand until the batter is retired, the batter becomes a runner, the inning ends, the batter is substituted for by a pinch-hitter or the pitcher incurs an injury. In the event a pitcher switches pitching hands during an at-bat because he has suffered an injury, the pitcher may not, for the remainder of the game, pitch with the hand from which he has switched. The pitcher shall not be given the opportunity to throw any preparatory pitches after switching pitching hands. Any change of pitching hands must be indicated clearly to the umpire-in-chief.
What I expect will happen is he will have checked all switch hitter stats prior to the game and know which side they hit best. So say Caminiti is up and he is a 4L. Venditte probably chooses to throw right handed so Caminiti hits from the left side like he does against all RH pitchers. Next hitter up is Eddie Murray who is a 4R. So Venitte toes it up ready to throw left handed. Murray then prepares to bat right handed like he does against all lefty pitchers.
The logic should not be all that difficult to program.