How to isert subtitle file in full blu-ray movies?

Hello,
How can i insert external subtitle file to full blu-ray movie that is in structure of BDMV folders?

I know that in Streamers it works if I put the subtitle file in the main BDMV folder and give it the name: index.srt.

But its not working that way in Kodi (if i remember well, it worked in the XBMC generation…).

Thanks, Bow