I have good news especially for those who can not bitstream over their cards.
I've given it a go with my 460 and with new beta drivers and my 5450 and CCC 10.9 hotfix:
PDVD10 2113.51.
Streaming Uncompressed PCM:Original PCM is 96/24/2 and 96/24/6:
Output mode: "non decoded high definition audio to external device"
No downsampling, no downmix.
Decoding lossless formats to PCM:Original THD/DTSHD-MA is 96/24/6:
Output mode: "PCM decoded by PDVD"
No downsampling, no downmix.
(ReClock downmixes in both cases to two channels even it doesn't downsample)
Here is the common SS:

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