Foreign Audio Search... don't kill me :)

[i228]

I'm encoding all my DVD library to a NAS setup into mp4 format streaming to XBMC on ATV2. So far I have the quality settings down to almost match the DVD quality video (the colors are slightly off/faded if you're really looking for it, but not by much at all)

One of my main question is subtitles. I've gone through numerous forums and cannot find an answer for my needs. I included the English both forced and not forced, these work fine if I ever need them. However I have some movies that seem to have the subtitles already burned into them, if I were to select Foreign Audio Search check "forced" and "burn in" would this burn the subtitles over the already burned in subtitles? I ask this because I've read that some movies like Salt require them to be burned in with Handbrake and then movies like Avatar already have them burned in, I don't want subtitles over subtitles.

Thanks in advance!