It turned out that the original layout of the HomeAutomation Board was far from perfect. From time to time I needed access to the USB hub to pull out or plug in an USB extension. This was almost impossible as the USB hub was located to far behind the wall. After fiddling around for quite some time I decided to give the whole board a re-design.
The key difference is now that the USB hub is the 1st item on the board when you try to access it. Which turns out to work perfectly. Especially as I will start my experiments on the Raspberry Pi with the CUL device which is during normal operations connected to the USB hub on the board.