Comment 30 for bug 348353

pcm.a52 {
   @args [CARD]
   @args.CARD {
       type string
   }
   type rate
   slave {
       pcm {
           type a52
           bitrate 448
           channels 6
           card $CARD
       }
       rate 48000 #required somehow, otherwise nothing happens in PulseAudio
   }
}

I tried the above. Works for Pierre in Fedora, but doesn't seem to work for me in Lucid.
See https://tango.0pointer.de/pipermail/pulseaudio-discuss/2010-July/007512.html

If I replace $CARD with 0, it works for me.

Can someone please try this and let me know if it works?