Closed captions are not subtitles! Closed captions are part of the video stream and are decoded by the TV during playback, whereas subtitles reside as a separate stream in the VOB. Closed captions can be turned on/off via TV remote, indicated as CC1 or CC2 in the TV menu, and subtitles via DVD remote. You usually see closed captions as white letters on a black background and subtitles as varying 4-bit color.
@ukchap, I think you mean subtitles. The software you mentioned would allow you to select which subtitle(s) you want to keep.