Nexus 7 software buttons not working

I’m trying to get the Nexus 7 software buttons to work but they don’t seem to respond. I thought they’d be the same as the normal hardware buttons on android devices but it doesn’t respond to the same keycodes.

I’m using code like this from the sticky thread on hardware button.

if (Application.platform == RuntimePlatform.Android)
{
if (Input.GetKey(KeyCode.Home) || Input.GetKey(KeyCode.Escape) || Input.GetKey(KeyCode.Menu))
{
Application.Quit();
return;
}
}

the reason is so much,in this test code,maybe you can try to do like this:
if (Input.GetKey (KeyCode.UpArrow))
print (“up arrow key is held down”);
if (Input.GetKey (KeyCode.DownArrow))
print (“down arrow key is held down”);