Problems with playing audio in OS X 10.8.2

I've got a stereo system Microlab Solo 7c and active subwoofer Sony SA-W2500.Both these devices need mini-jack 3,4'' to connect it to PC. In Windows I just used 5.1 configuration with disabled rear and center speakers. Can I use it in OS X 10.8.2 (with external USB sound card) to play audio files using all of my speakers? I already purchased sound card Terratec Aureon USB 7.1. Any suggestions?