nonCanon flash and Live View (T2i)

As a test, I took the triggers out of the equation, placing the flash directly in the camera hot shoe... non-Liveview triggered the flash; Liveview did not.

I've been told in another forum that the yn-568 flash will trigger in Liveview mode.

So what is the deal here?

This is important to me because my nifty-fifty focuses more accurately with Liveview, so I want to use liveview with it as much as possible, including when I use the flash.

Any insights are appreciated.