I found a way to solve the non-responsive keytrack and mouse from Chinese Mac forum.
The solution is quite easy:
1. Reboot the MBA and press "option" key
2. Choose to boot Window from "bootcamp startup memory stick"
3. It will load a new Setup for the Win8 installation. Go through the process, enter the product key and go to the selection of harddisks in MBA.
4. Choose the one prepared for Win8, usually the bottom one (previously set by disk utility in Mac OS)
5. Choose "load driver" option, then go to bootcamp startup memory stick folders:
Bootcamp->Drivers->Intel->Chipset->WIN7->
Choose "Intel 8 Series SMBus Controller - 9C22"
6. After installing this driver (which should be for touchpad and mouse), quit the setup. MBA will restart automatically
7. Press "option" key, choose to boot Window from the hardhisk (not the one from "bootcamp startup memory stick").
You should be able to setup and use your Win8 without a problem now.