Why does the video that I have on my USB Memory stick not output via the rear monitor wire?

It seems that the unit only outputs DVD/iPod video.

 

I'm at a bit of a loss.

I was hoping to be able to play video to other screens from the USB (I can put more on the one that I have than a DVD-R)

 

Is there a setting I am missing or is it just the way it is?

 

Thanks in advanced