I just completed my build with the Gigabyte H77N-wifi, i5-3570k, Sandisk 480GB SSD, 8 GIG Corsair Vengeance Low Profile memory, and the Startech firewire board (PEX1394B3), and can neither get the computer to sleep nor shut down. The computer powers up again in a couple of seconds by itself.
HOWEVER, when I replace the Startech board with a cheap Syba SD_PEX30009 board, all is well. Sleep works as does shut down. So, at the moment, the cheap Syba card beats the expensive native StarTech board.