Failed Closed Captioning in Ibooks Author

I am currently developing a textbook using ibooks author with tons of videos. I've followed the guidelines on how to add closed captioning to each video and have done so. (here is the guide I used to attach CC files to my videos: iBooks Author: Adding video content with a closed caption track - Apple Support)

The videos play correctly when I test them on my desktop via quicktime. The options to turn CC on or off appear on the player interface.

When I then bring the videos in to my Ibooks Author session, it seems to completely ignore the CC options and there seems to be no way to access the CC when I test the Ibook on my Ipad. At first I thought I hadn't set up the right accessibility settings on my ipad, but even after turning CC on in the settings, no CC options appear in the player windows on the ipad.

Please help!