Some people have no issues getting Net Shares to work properly with the WDTV, while others spend days pulling their hair. I don’t know what critical step some people are missing. I’m one of the ones that just shared the files over, and they showed up and played fine, so since I never had to really trouble-shoot it, I can’t personally suggest what to look for as to why it isn’t working. I know there are dozens of threads with users trying to help others get it to work, but I don’t specifially recall a “smoking gun” step that gets overlooked.
Anyway, don’t let me confuse you. If you have the codec pack installed, you can still FF/REV from within WMP – you just can’t skip around from chapter to chapter (if your .mkv file has chapters). But I just double-checked, to make sure I wasn’t giving you bad information… when I use “Media Server” to pull a .mkv file from the PC, the WDTV _ does _ have chaptering ability, as well as FF/REV. I can go into “Options” while the file is playing, and pick whatever chapter I want, and the WDTV just goes where I tell it – it doesn’t know (or care) that WMP doesn’t like .mkv chapters.
So, other than the fact that WMP doesn’t report a length to the WDTV, the .mkv otherwise plays exactly as if it were accessed locally.