Text track vs. subtitle

I've recently been using HandBrake to encode some episodes of a TV show from a DVD into m4v files. My goal is to be able to watch them on my iPod Classic with:
1) chapters
2) the original language track (Japanese)
3) the English language track and
4) soft subtitles.

HandBrake does a great job with all of those things except the soft subs, so I decided to make them myself.

I used TitleLAB to convert an srt file into a QuickTime text track, then I added the text track to an m4v that I made with HandBrake. With the {keyedText:On} attribute and the proper display offset (under Properties > Visual Settings), QuickTime plays the text at the bottom of the movie's window switching between the plain and italicized text as I programmed it to do. VLC plays it minus the italics, it evidently doesn't support QT's {italic} attribute. It would look perfect if only the {outline} attribute had worked (but that's a question for another time).

The problem I have is that after I save the movie as a self-contained movie, even though my text track looks like a subtitle, QuickTime doesn't recognize it as a subtitle. That is, when I go to the View menu and check the Subtitles submenu, it's greyed out and says "Off." iTunes also reports that there are no subtitles in my video, but it will play my text track! My iPod doesn't play the text, even when subtitles are turned on in the video settings. Interestingly enough, the text is visible in my iPod's thumbnail image of the movie.

In my iTunes preferences, subtitles are set to display in English, and closed captions are turned on. QuickTime is set to show both subtitles and closed captions when available. It seems like I need to tell QuickTime somehow that I want this text to be a real, honest-to-God subtitle, not just a measly text track. Does anyone know how to do this? What's the difference between a text track and a subtitle track?

My iPod software is the latest version, unfortunately I forget what number that is. 1.1 or something.

I've tried opening my srt file directly with QT and Perian, but it didn't work. I downgraded to QT 7.3.1, even installed FrontRow Trailers to get the Perian 1.0.0.2 update, but it still wouldn't open. I've read that Perian can open avi movies with identically-named srt files, but either it does not open m4v movies with identically-named srt files or I'm doing something wrong. Any ideas?

Sorry for the long post, but once again, my question is about how to make a track that QuickTime will believe to be a subtitle, not just an ordinary text track.

Thanks in advance for any suggestions.