Monitor in Portrait Mode

I'm new to the site and I'm in the process of setting up multiple monitors.  On my glass cockpit, i have three touch screen monitors.  I'm able to get them all to work just fine, but I would like one of them to operate in "portrait" mode.  When I rotate my monitor in the set-up in my nvidia card, then go to display settings in fsx the display is not recognized.  Rotate it back and fsx sees it just fine.  Does anyone know how to set just one screen up in portrait mode, all others will operate in landscape mode???

Thanks in advance for your help.

Tim