You use HDMI for audio? Using amp for sound?
Your HDD is external 3.5"?

You never reply if you using amp for sound or tv/monitor. I'm guessing no amp, otherwise dts can be decoded.

Looking at the pdf file, did you set the audio as DIGITAL or STEREO?

Also, if the sound is DTS, you need an amp/receiver to decode. Your plasma can only have sound for other than DTS now.

What home theater you referring to? Why not hdmi WDTV to hometheater to plasma (instead of WDTV to plasma to hometheater)?

Bro, do check if your Panasonic HT system  come with any AUX input (in optical)  which can detect and decode DTS and DD5.1 tracks. Use that to link to your WD HD Media player (to be configured as Digital output) for any audio playback via optical cable. As for video, hook on a HDMI cable from your WD HD Media player directly to your Plasma (Make sure u select the right screen size and signal -> 1080i/p?)

Good luck on your test!

Now, something that I want to share. This HD media player cannot recognise chapters for DVD VOB file. The player also do not have any time search feature to jump into any scene. Say for a 2 hours movie clip, if we need to goto time 1hour 35 minutes.. we have to FF (up to 16x speed ) all the way till then!

No problem on VOB file playback, can get all subtitles

No matter if the the subtitle already embedded in MKV, it'll not display it. You have to extract it using MKVExtract tool. Hope this will help.

tested just now
most of my mkv files were played flawlessly
except few files with different flaws

anyway, i was using the composite cable to test
tomorrow gonna get a HDMI cable to test again
to see whether the flaws can be resolved

about the subtitle
yes, all the english subtitles can be shown
but not the chinese subtitle
not even a single word was shown

the subtitles are the srt type
the so called 3rd party subtitle
not the embedded one
I tested one mkv movie with embedded subtitle
it shows nothing
I think like metalgrindsolid bro mentioned
need to extract the subtitle out

when i opened some of my mkv files
it shows that the audio track type is not supported, no sound
maybe not all the digital audio track types are supported?

does this has co-ax out?

For no sound problem, it's already mentioned before.

DTS can only be heard via AVR/amp with dts decoder or using optical cable.

It's something to do with licensing if DTS is to be downmixed to DD.

I'm assuming either your HT cannot decode DTS or you didn't set audio settings to digital.

use mkvextract(available with mkvtoolnix), add the video and just extract the sub
you might want to convert it to .srt if it's in .ass format using subtitle workshop

Or easier to just search for and download srt from net.