Inviyya works fabulous on Vampires (tested it a lot on my V1200), but you need a floppy drive. The game is switching off the OS and uses a special loader for maximum performance on A500 level systems.
Since the SA doesn't have one, that's where the problem lies, I guess.
The full game version will have a whdLoad slave, so that will cover you on that front...
Hope you will like the game, looking forward to your feedback.