Anyone got creative desktop theatre?

I’ve just got the creative Surround 5.1 pack, with Live! Player 5.1 and Desktop Theatre DTT2200 speakers, and its given me nothing but grief! Sound is something i’ve never claimed to know much about, can anyone tell me how i can watch a dvd and get full dolby 5.1 surround sound? As i said ive got the live! 5.1 card, desktop theatre dtt2200, hitachi 7500 dvd drive and i use Hollywood PLus software to playback through a RealMagic card. Currently i have the three channels running from my card to the speakers, as creative instruct, and i can listen to mp3’s etc through all 5 speakers. I can only get sound from the dvd player when i select the analogue surround setting in options > settings. I get nothing from the Digital options. Do i need a new setup hardware wise?

Any help would be much appreciated, the set up seems great but im sure im not using it to its full potential!!!