Problems connecting two Xtion to Windows 7 64

[Waterplant]

Hi Guys,

i am trying to connect two (and later three) Xtion to one system.
I develope under Windows 7 64 with the OpenNI driver "1.5.2.23 Development Edition".

Ok - now the problem: Connect the first device => eveything is fine.. connecting the second xtion causes a Windows error "Device could not be started" (translated)
What am i doing wrong? How can i fix it?

And the next question... when i will manage to connect it. How can i set or read the device_id for using it in PCL?

Thank you very much :)