i am writing this now from the running tower system
thanx for the help. especially the pciinfo tip did show up that the card was not recognised, so was the network card.
to be honest, i don't think, the mediator and|or d-box are a masterpeace of engeniering, because the reason the boards were not detected, was that every time i screwed them down, they were lifted up a little on one side of the pci bus, so connection was not enough. rearranging the cards i could solve the problem, as the usb card seems to be strong enough connected to the board to lift the mediator a little to be able to screw the other board down too.
finally everything works, except the floppy, but a am sure this is a connection problem too, have to check this later.
now i am too happy and one step closer to a world free of pc's
thanx