My guess is that your EDID is well patched (if you could dump and attach one, I can confirm or not)... So, beware that you MUST use a media player with codec supporting bitstreaming and configured to do so (e.g. LAV filters or ffdshow), and TV will then offer surround output during video playback (only, not while being "on the desktop"

If still no luck, here's one ready-to-use F-MST driver patched to support DD/DTS 5.1. Go into Windows device manager, and update driver of your TV (surely "generic plug n play monitor" or something like this. If you have more than one (attached screen), check properties->details tab->Hardware ID, should be MONITOR\SAM0xxx) using that inf:
Statistics: Posted by zoelechat — Thu Jun 25, 2015 10:13 pm — Replies 8 — Views 874