I managed to stumble on a trick that let's you hit a high arcing ball that is unvolleyable. It can be picked up after the bounce, but before the bounce it's unreturnable--in some cases even a smash goes into the net. Plus, hit just right it completely confuses the computer. I've got a little video demo of me versus a computer (all stats maxed out, computer on hardest difficulty). Kinda hard to lure the computer into it, but I got a few in a row halfway through. Oh, and this is the 2k4 version for mac.
http://video.tinypic.com/player.php?v=477zhua