the mainboard is now free to be pulled out. It is not too difficult but you have to be careful. I grabbed on the most stable components like the PCMCIA cage and carefully pulled it towards me. In order to free the left metal fingers of the PCMCIA cage you have to slightly pull the casing outwards a little bit, otherwise they get stuck underneath.

as soon as the PCMCIA cage is free from the case you can pull the board out.