VLC + Audigy 2 ZS + Onkyo TX-SR503 AVR = No Dolby or DTS

[shinto]

I am using a mono baby plug cable to stream digital signals to my Onkyo amp through its Coaxial In.

I have set my VLC to A/52 over S/PDIF under the Audio menu but the sound does not come out right, sounds like it is skipping and repeating and stuff. The file is a VOB format of a Dolby Digital trailer, I also have a couple of DTS format audio files and the same result as well when selecting the A/52 over S/PDIF function. The appropriate format is successfully detected by my receiver whether DTS or Dolby. But when I use VLC's built-in decoders it works well but my receiver does not do any conversion.

I have also done the necessary settings for my soundcard, like SPDIF passthrough and enabled/disabled Audigy's built-in decoders and stuff. On PCM Stereo signals I have no such problems.

By the way, I'm on 2.0-ch mode since I haven't completed my Hi-Fi setup yet. I also have tried 5.1-ch mode on my receiver but the same results.