I have a mybooklive and a new Samsun MU7000, like others I have found that if you stream MP4 etc to the TV you cant pause, fwd etc which is really annoying.
I looked around and the solution people were suggesting was to install a newer version of Twonky (instead of the default version 5) I didn’t really want to do this.
I found this solution - https://cialu.net/wd-book-live-dlna-streaming-issue-samsung-smart-tvs/
Which basically means you SSH to teh mybooklive and edit the XML file on the Mybooklive and change the entry for the samsung TV slightly. After this I am able to pause/FW etc as normal.
I thought this might be helpful for someone else.