The Creative Z sound card does Dolby digital live(also has DTS connect) but it is 5.1 but really 7.1 on headphones is pretty much a fallacy anyways using only 2 speakers but it is simulated 5.1/7.1 surround anyways.
Optical can only do uncompressed 2.1 and compressed 5.1/7.1 audio anyways. The only way to get true/discreet channels of surround is by analog, HDMI or display port.