Bootcamp driver - unsupported on this computer model (How to install Bootcamp driver on mid 2009 Mac)

Step 1. Download Bootcamp driver from Apple Website (In my case, use Bootcamp 5.1)

Step 2. Run cmd as Administrator.

Step 3. Go to the downloaed directory which "Bootcamp.msi" located, run command below to install.

Step 4. After rebooting, U could see Boot Camp Control Panel and enjoy your Win 8 in Mac!