Panasonic and subtitles

Hi all, I have a Panasonic E5B which works great with Serviio using the E/S/ST/V 2011 profile. However I have a mkv with subtitles, and it won't display the subtitles on that profile. It DOES display them using the generic DLNA profile, but then I don't get sound.

I have all the subtitle boxes ticked in the delivery tab, there must be something different between the two profiles that is stopping the subs from displaying. Anyone know what it is?

Thanks

Looks like I'm having the same issue as this post - viewtopic.php?f=13&t=10349

Not sure what the "packet video line" is though?