Adding External Subtitle

[thpierce]

Having problem getting External subtitle to appear in a .iso file. I'm making a Main Move copy of a 3D movie and I'm trying to add an external .srt file to the iso copy.
I uncheck the subtitle files on the DVD and add an external srt file. When I play the iso file the subtitle is available as an option but does not appear in the movie. Any suggestion?

[vitaei]

and I when copying 4K of the disk when adding external subtitles Russian gets ill add support for Russian subtitles