You wont be able to cut the board anywhere it has leads from the num pad to the usb output. It most likely will be too complicated to tell what goes where. Also if you do manage to cut the board and preserve the numpad leads you could still end up with a dead usb device. -also I wouldn't hack away at an electronic device without knowing what you are doing. There's a chance you will damage the computer you interface it with.
This might not not be enough info to hack away at the board but I'm hoping it might be enough that you wont