Problem with oreintations xna windows phone 8 monogame

Hi guys, hopefully someone can help me out.

I want to have a locked landScapeLeft but it keeps switching when the phone is rotated.
How do I stop this and have it locked at a certain landscape.

I have tried the following with no luck : (

SupportedOrientations=“Landscape” Orientation=“LandscapeLeft”
graphics.SupportedOrientations = DisplayOrientation.LandscapeLeft;

Thanks in advance.
Jay