Quadro 4000 display problem

I have a newish Mac pro that I just upgraded the graphics card to the Quadro 4000. Problem is that my second display, an Apple 27" monitor feeding off pthe mini port via their mini port apple display adapter, is not showing up. the main display, a 30" monitor via the DVI connection on the card works fine. As a test I hooked up a smaller 24" display to the second port to see if it booted up, it did. So, then I swapped the monitors. 30" to second mini display port and the 24" to the main DVI port. Only the small,24" monitor showed up. So, I am wondering if perhaps there is a resolution cap on the second mini port. Nvidia tech support says no that even the 30" should display off that connection. Any thoughts out there?