I wanted this functionality as well. While I was unable to find this in the drivers, I was able to get similar results using the following:
1) Configure your X to use 2 screens (not twinview). My setup has a TFT monitor as screen 0 and TV as screen 1.
2) Play your video content on screen 1, and it displays on the TV.
My XF86Config file can be found at my site
My weapon of choice for playing video files is mplayer, which has a command line option for selecting the screen to display on. Any video player should do, but if it doesn't have a command line option for selecting the screen, you must set your DISPLAY environment variable before starting the video player. Also mplayer leaves a control interface to the shell, which helps
This solution has some limitations: The video is not displayed on the primary monitor at all, and the TV is not much use for anything else. I use the TV just to display full screen video, so this solution works for me.