Hi Torben Nielsen,
Since you've already established that the touchpad works in Linux, you've done a useful test that helps narrow this down.
As a next step, check the BIOS/UEFI for a setting such as Touchpad, Internal Pointing Device, or I2C and make sure it is enabled. If everything there looks correct but the touchpad remains missing from Windows Device Manager, I'd recommend asking Cepter support for the exact Windows I2C/Serial IO and touchpad driver package for your model.
This would be preferable to experimenting with generic touchpad drivers. I hope this helps move the troubleshooting forward.