Ah, first: Thanks for your answer! I was near giving up and sending the card back...
Ok, I started xmms and chose for the output plugin "ALSA lib". Configure brought me to a list of devices, I chose "ICE 1725 Surround PCM (hw0,2)". So far, so good; but xmms wont play a song. Starting it from command line showed this error message:
** WARNING **: alsa_setup(): Sample format not available for playback
I think this is because I didnt configure this surround40 device, but I dont know how
I looked around on my system and discovered in /usr/share/alsa/pcm the file "surround40.conf", but its full of vars I cannot fill...?
How do I configure the surround40 device?
Thanks in advice!