Viewing Subtitles created with Handbrake

I've read that AppleTV2 will display soft subtitles (embedded in the video file but not burned into the video image) on an .m4v movie file.

Using Handbrake, I've converted a DVD enbedding the subs using both the "Normal" and "Default" settings in Handbrake (I haven't tried using the "Forced Only" setting yet)

I can get the subs to display using VLC, but not QuickTime or the AppleTV.

I've found that pressing the Select button then the Menu button of the ATV2 aluminum remote will bring up a chapters and audio select menu on the TV screen - but there's nothing there for the subtitles. Is there a different button combo for subtitles?

What do I need to do (short of burning hard subs into the video) to get the ATV2 to display soft subtitles?

Any info appreciated.