um, i'm not sure thats the right product....
reading the description and looking at it, i think thats simply to convert a toslink connector to a 3.5mm optical connector............far as i know, the 3.5mm jack on the back of the Audigy 2 (which i own and use myslef) only outputs an electrical signal, not an optical beam..........an older Creative card i had used a 3.5mm optical output to normal toslink (cant remember if it was on the card or the breakout box tho)....
so this thing may not be what you need........i think you need something more along the lines of a signal adaptor box to convert from digital coax to optical......
(my reasons for this? look at the 3.5mm bit, it has a small lens or fibre optic ending on the bit that first goes in to the hole on the soundcard.......this suggests it needs to receive an optical beam from the soundcard........which i dont think the soundcard emits, at least not from the backplate.......i think you might find it would be better to ask this question again on the Creative forums, they have some good helpful people there just like here.....also you could check the full spec on the soundcard with the knowledgebase..........if it turns out this is the case, you might wanna look in to buying the breakout box, if you have a spare slot on your puter where you normally put CD/DVD drives then you can fit it in there, shouldnt cost much for the breakout box now the new X-Fi cards are released.....)
i may be wrong, but its worth checking out with the Creative forums first to save yourself a couple of quid....lol