Microsoft surface 2 and gyroscope desktop

Hello, I developp an app with unity 4.3.4. My app need to work with microsoft surface pro 2 under the desktop. Everything works fine but I need to control my camera with gyroscope. My script works under ios or android. But under windows I can't activate the gyroscope, I'm trying in the Start function of my script Input.gyro.enabled=true

I also try to see if gyroscope is supproted on my tablett and the function SystemInfo.supportsGyroscope return false.

But the Microsoft surface pro 2 has a gyroscope.

What can I do to activate and use the gyrosocpe with miscrosoft surface pro 2 (windows 8 desktop) ? Thanks