Fullscreen HMD Stereo with Vista64

[xabbu]

Hello,
I am trying to get my monitor configuration right using the following setup:
My workstation has two nvidia 295 GTX boards each offering 2 DVI outputs (Non-Sli Mode).
On the First board and first DVI output I have connected a tft monitor.
This monitor is set as the Primary Display in the Vista display properties.
My HMD (nvisor SX) is connected to the first and second DVI output of the second nvidia boards. So in windows it is connected to monitor output 5 and 6.
These two outputs are setup to extend the primary display.

What I am trying to do is to run Vizard's 3d-View in Fullscreen mode and in Stereo/HMD mode on monitor output 5 and 6. This way I would still be possible to work on the computer with the primary display. I allready found the option to switch the fullscreen monitor via
viz.setOption('viz.fullscreen.monitor',2)

This will switch to fullscreen mode only on monitor 5 and will display the two splitted 3d views only on monitor 5. So it is not spanning the view over monitor 5 and 6 in order to drive both displays of the HMD.
As vista does not permit the horizontal spanning of the desktop over multiple monitors I am wondering how I could achieve what I am trying to do.

If I do not set the viz.fullscreen.monitor it is actually spanning over the first two monitor outputs of vista (primary display and first extended one).
So I am wondering if it is possible to put an offset on the monitor number from which the spanning for the stereo/HMD output will begin.

thanks in advance for any solutions/advices...