revised sub/soundcard conflict

I have a new soundcard (Hercules Fortissmo II) and I can’t get it to detect my Altec Lansing ACS340 subwoofer. Everything is physically hooked up correctly according to the Altec directions. I have unistalled and reinstalled the soundcard drivers. I have toyed with the Fortissmo soundcard settings. The subwoofer works fine, I have tested it on a different computer system and through my discman. I get sound from the speakers, just no subwoofer stereo. I was wondering whether this problem is fixable or weather I should return the Hercules card for replacement card or just get my money back all together.