Cannot make subs for foreign language appear

[MaxPlanck]

I've always used Megui to encode my standard DVDs. I recently started using it for blu ray discs, but I've found that a movie which should display subtitles for portions that are spoken in another language, do not appear. For instance - I encoded the movie "The Hunt for Red October", which at the very beginning features a scene spoken in Russian, but the translated subtitles do not appear. I never had this issue with standard DVDs. I hope I'm describing my issue properly - is there an additional step that I need to take to make Megui include this during the encoding process?