Xbox One HDMI input (pass-through)...Surround Sound from PC not possible?

I am also having this issue.

The beta surround sound feature only pertains to passing through surround sound received over the Xbox One's HDMI input from (e.g.) your cable box. See

support.xbox.com/.../digital-sound-not-working

It does not enable Dolby Digital over HDMI either. As for connecting your Xbox to your TV via HDMI, setting the Xbox to output DTS (or, whenever MS finally makes it available, DD), and expecting your TV to output that DTS/DD to your receiver via optical
out: please realize that very few TVs support passing DD from an HDMI source out via the TV's optical out and even fewer (if any) will pass DTS. In most cases, you will need to connect the Xbox One's optical out directly to your receiver to get surround sound
(or, better, just get a modern receiver with HDMI inputs, which cost less than the Xbox for an entry model).

From Support:

Basic setup with an audio/video receiver

With an audio/video (A/V) receiver, the best and most direct option is to connect the devices sequentially:

1.Connect your set-top box HDMI output to the Xbox One HDMI input.

2.Connect the Xbox One HDMI output to your A/V HDMI input.

3.Connect your A/V HDMI output to the HDMI input on your television.

Notes

•This option requires that all devices support audio over HDMI.

•Surround sound from your set-top box will not be passed through the Xbox One.

•When you perform this kind of basic setup with an A/V receiver, you’re passing both audio and video through another device. Depending on your equipment, there is a small risk of audio or video lag.

I always recommend running S/PDIF for audio surround sound. It eliminates an 'extra' pass-through of the AVR. There is a beta of the HDMI surround sound pass-through, but that particular function is indeed beta. Although technically if you wanted surround
sound for everything (I imagine you would...) 2 S/PDIF's one from the cable box, one from xbox to the AVR. Not 100% ideal, but we are working on it. The Xbox One is a constantly evolving eco-system, the console you see today will not be the same console in
6-12 months down line. Thank you for understanding and your input, we will continue to release updates for more advanced and better features.

-Cheers

Currently, the xbox one does not support digital surround sound via HDMI pass through. I believe they are working on a fix for this.

If you need surround sound, you could perhaps use a S/PDIF digital optical cable from the xbox to your surround capable receiver