In the end, here is what worked for me:
1. Using SAF 5.2 as codec pack in general. All movie formats work like a charm.
2. As Audio player i use "internat dshow player"
3. In addition i installed AC3Filter and set it up for spdif pass through for dts files.
4. Then i disable "uncompressed" in the codecs tab of ffdshow audio decoder config
When i start Graphstudio now with an audio dts file (.dts) it only uses AC3filter and plays the audio files in pass-through mode on my AV Receiver.
I know its probably not the best way to do it, but its the one doing what i want it too.
SAF6 will paly yout DTS in WAV without any problem.
AC3 filter is not capable to play HD audio, but it will load to decode it = no sound.
Some reciever have problems if the DTS is in 44.100.Hi,
I'm using SAF 6.09 and I have the same problem.
My htpc is linked to my AV by hdmi (set passthrough), I don't use Spdif.
What is the solution with hdmi?
I just putted all waves into an .mka container. Now it runs fine.