Serviio

Hello everyone, I'm new to this forum and to Serviio.
I just installed Serviio on a windows 7 machine and it works pretty good. I have a BD-D5300 player from which I'm able to stream
mkv also with subtitles support. The only "strange" thing is about multiple subtitles. If I have this files in the serviio library:

my_movie.mkv
my_movie.srt

everything works ok, the strange thing is that when I press the TOOLS button, under "Subtitle Language" I get "on" or "off".
So I tried to put these files in the Serviio library:

my_movie.mkv
my_movie.en.srt
my_movie.it.srt

but again, under "Subtitle Language" I only get "on" or "off".

Is that a limitation of the player or I'm doing something wrong in Serviio??

Thank you guyz