Auzen X-Fi Prelude - no auxiliary sound?

Hello!

Maybe someone can help my with my little problem...

I have a source (my turntables ^^) connected to the auxiliary-in of my Auzentech X-Fi Prelude soundcard, and the spdif-out of the soundcard is connected to my dolby digital receiver via optical cable. My problem is: I can see the signal of the auxiliary-source reaches the soundcard, since the EQ shows the amplitude, but it's not being played via my speakers. Listening to mp3s, watching movies with sound etc. all work fine (even without dolby digital live enabled), the only thing that won't work is getting that signal from the aux-source routed to my speakers. why is that? I can even record the signal from the aux-in and listen to it afterwards, works great – it's just that I can't hear it while its coming in. Any ideas?

Sincerely