How to transfer srt to iPad using itunes

Hello all,
I want ask something, how can I transfer srt files (subtitle files) into iPad using itunes ???
I know another way to put srt files on movie, but I want to use feature of Closed Captions + SDH in iPad (Accessibility -> subtitles & Captioning) because I think that you can enable or disable subtitle in anytime you want by enable or disable this feature, but if it merged with movie you can not stop iad

Thank you in advance.