I have the same problem (Sony Bravia 2010, EX500), and I will upgrade FFMpeg to try to solve it. Although, pause/play and fast forward does work when I'm using Serviio through my PS3. How come? Is it possible to change the Bravia profile to make it work with the tv as well?
Using:Ubuntu 11.10 64-bit
Serviio 0.6.2
Edit:I upgraded using the PPA earlier in the thread, and it works great. I'm convinced this is the best solution, but I'm still interested in the details as to why it was working on the PS3

Here's a bit simpler method of upgrading ffmpeg:
1. Open a terminal* and write/copy this and hit Enter (you'll have to confirm with an additional Enter also):
- Code:
sudo apt-add-repository ppa:jon-severinsson/ffmpeg
2. Then open the Update Manager and do an update,
but refresh the lists first!
* You can open a terminal quickly by pressing Ctrl + Alt + T