Forcing UIViewController in Landscape

I have a UITabBar. In the first tab,开发者_Go百科 I have a UINavigationController. Within that navigation controller, after a couple of UIVIewController are pushed onto the stack, there's a UIViewController in which the user can use their finger to sign.

I want this to be in Landscape mode. How can I force my the phone to turn into landscape? In that signature view controller, I implement supported orentiations function and return landscape right but still nothing happens.

Thanks.

Tab bar controllers support a portrait orientation by default and do not rotate to a landscape orientation unless all of the root view controllers support such an orientation.

So sayeth Tab Bar Controllers and View Orientation.