Well depends on what coding you used to "shut the screen off"; Flip calls the libosso "osso_display_state_on" method to wake the screen when an alarm occurs; if your code does something to override the screen state (i.e. sets the brightness to 0 for example), then this code will not have any effect (the tablet will "Wake up", but the screen would still be at 0 brightness since that's what you had it set to before). If you let me know what code you used to modify your power button I can try and toss the "Wakeup screen" code into the app if it's easy. The other thing you can try is put Flip into Insomnaic mode, then set your alarm as usual and exit the app. Turn your screen off as you did before, and see if the screen comes back on when Flip's alarm is triggered.
(This might work since Insomniac mode automatically overrides the tablet's brightness level, but might also NOT work if your code has changed some system wide brightness configs).

0.9.5 is stable, I just goofed when I first posted it as I mixed up the Diablo and Fremantle packages. And I still can't get this darn thing to go into Extras-devel for Diablo!... no idea why!

Thanks!