UPDATE (20/Oct/2012): I've also tested U.S. DVB subtitle (technically, Closed Caption tracks) rendering. The test file, as usual in my 1080i60 U.S. DVB MPEG-2 tests, was THIS MPEG-2 + AC-3 + CC file. (In the original article, I've only tested European DVB broadcasts, which use another technique for subtitling: bitmaps. In the US, technically, an entirely different, textual closed captioning method is used.)
Unfortunately, as you can also see in the screenshot below (see the annotated "Subtitle" group containing nothing), it didn't even recognize the CC tracks, let alone rendering them: