I have a new home server, and installed windows 7 64bit there (only for testing stuff). And of course, there are so much more driver problems then on linux / ubuntu.
Anyhow, JimboHQ has solved the issue. Thanks a lot!
I copy here for future reference:
1. Download and install the 1.07 driver from: http://support.lenovo.com/en_US/detail.page?LegacyDocID=MIGR-73235
2. Plug the keyboard in. At this point the keyboard functions but neither the trackpoint nor the touchpad work.
3. Click Start, Devices & Printers.
4. Under devices, choose "IBM USB Keyboard with UltraNav" (You won't see this unless you've installed the 1.07 driver).
5. Click the Hardware tab and find the 1st instance of "Synaptics Composit USB HID device"
6. Click Change Settings, select Driver tab and select Update Driver.
7. Click "Browse my computer for driver"
8. Click "Let me pick from a list of device drivers on my computer"
9. Select "USB Input Device", then Next, Close, Close.
10. Your trackpoint should work now. Repeat steps 5-9 on the 2nd instance of "Synaptics Composit USB HID device" to get the touchpad working as well.