Converting sub/idx files to work with SBS 3D file

I am looking for a way to convert sub/idx subtitles to display correctly with an SBS 3D file. I have found a number of resources for converting .srt files, but nothing for vobsubs. The subtitles I want to display are in Japanese, for which the OCR tools that are available are not terribly accurate.

Is there some tool available that will allow me to convert idx/sub subtitles directly to 3D idx/sub?

Thanks in advance.