X switchs physical outputs

[humi]

Hi i've a a small problem.

i connected last week a second monitor. The redmond-system use both monitors as they are connectet output1 -> monitor1 and 2. -> 2.

X always use ouput2 as screen0/card0 and output1 as screen1/card1. It's not a big problem, but why???
I tried both config possibilities driver buildin twinview and Xorgs xinerama with two card sections.

I'm running gentoo with the latest X and nVidia-drivers on a Quadro4 980GLX.

I hope someone has a hint ...

thanks
humi