This is not possible, as I said, there's no options for the intergrated LAN card (I'm not even able to disable it). I only have options for the NForce2 LAN card, which I have disabled.
You said I could try to reassign the IRQ adresses in the bios, any suggestions where to search for these options? I found something where I can reserve IRQs, but if I reserver the 11, they both went to irq10.
I upgraded the BIOS to the newest one yesterday too, still no hope