Can I enable subtitles in iTunes U videos?

I have imported Coursera videos into my iTunes library and added subtitles with Subler.

If I watch videos in iTunes or set "Media Kind" to "TV Show" and watch them in "Videos" app on iPad subtitles are available.

But with "Media Kind" set to "iTunes U" when videos are uploaded to iTunes U app on iPad, there I see no button to turn subtitles on.

What am I doing wrong?

Thanks.