Help connecting sb to reciver

hello i have the creative sb audio g 2 zs sound card and i would like to connect it to my reciver i have the kenwood 6090d i have a problem that i hear a sound not but in low quality and the subwoofer does not work .
i plug the sb digital out to the digital in in the reciver and put the mark "digital out" on in windows xp and still the same problem .
does anybody can help me and tell me how to plug it curectly????