stream subtitles as dlna server

Hi folks

I have a old pc with xbmc connected both via vga and via ethernet to my tv.

if i play a movie directly through xbmc i'm able to see the srt subtitles, but if i use xbmc as a dlna server subtitles is not displayed.
is there anyway to fix this?

it is not a television problem, because using other dlna server i'm able to see the subtitles

thanks and regards
luca