Problems configuring 5.1 passthrough device

Hi,

I have a system with a soundcard (S/PDIF output) and with a graphics card that has a sound output via its HDMI interface. For normal playback xine uses Alsa-device 3, card 2 (which is the HDMI channel of the graphics card):

cat .asoundrc 
pcm.!default {
    type hw
    card 2
    device 3
}

This normal xine playback already works fine and uses HDMI for audio transmission. But I have big troubles configuring pass-through for 5.1/DVD audio data. With

audio.device.alsa_passthrough_device:iec958:AES0=0x6,AES1=0x82,AES2=0x0,AES3=0x2

audio is played via the S/PDIF soundcard which should not be used.

With

audio.device.alsa_passthrough_device:hw:3,2

nothing happens, I can't hear any sound.

So what do I have to configure to use the HDMI audio channel?

Thanks!

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