Set orientation to landscape in android on both sides

I am working in an android application in 2.2 and I want to set my application in landscape mode.

For that I added in my manifest with every activity tag android:screenOrientation="landscape" and it worked fine.

But it comes only in one side. If I turn the device again upside down it fit in the same position in landscape mode. How can I have landscape mode in both the side of the device. Please help me.