Just thought I'd share this info to save somebody the aggravation that I went through. I spent many hours on this site researching how to add the factory navigation screen to a Non-Nav 2006 Coupe, but nobody had really done it successfully.I know that a lot of people just go with a navigation equipped double-din head unit in the stock head unit location, but I wanted to have my navigation display in the higher stock navigation screen position for safer viewing and to maintain my Alpine IVA-W505 as a dedicated audio screen.
After buying a unit on eBay that contained the navigation screen and navigation switch, I consulted the Infiniti Service Manual to determine how to utilize the functions of these components. As shown in the wiring diagram that I have provided in my album, I was able to restore full functionality of the motorized navigation screen and the illumination of the navigation controls using wires in the A/C Controls wiring harness.
I removed the factory navigation screen from the housing and found that the Alpine TME-S370 Touchscreen was a perfect fit for the location (If you find another screen of similar dimensions it may also work). I added Alpine's NVE-M300 Navigation module for touchscreen navigation on the new screen.
Now that I had two screens to utilize, I added front and rear cameras to the system with control switches on the side of the center console.The upper switch turns the front bumper camera ON and OFF on the upper screen for more precise parking. The lower switch toggles the rear-view camera between ON and REVERSE on the lower screen as needed.

Hopefully this helps somebody that's interested in the same type of setup.

--------Components Used------------------------
-Factory Navigation Screen and Navigation Switch
-Alpine IVA-W505 Double Din Head Unit
-Nissan 27500-AC500 A/C Control Module (DUAL button and LED soldered from original board)
-JDM Double Din Finisher
-Alpine TME-S370 Touchscreen Monitor with Alpine NVE-M300 Navigation
-Alpine KCA-SC100 Sirius Control Interface
-Sirius SC-C1 Sirius Controller
-Alpine PXA-H100 Imprint Module
-Alpine KCE-400BT Bluetooth Interface
-PAC SWI-JACK Steering Wheel Control Interface

http://photobucket.com/paclypse71

How in the world did this post go more than a year without a reply. When I read your post, you had my curiosity. After seeing the pictures you have my attention. So can you still access the maintenance screen on the factory unit?

Nope.

Different system attached to the screen.

No, the system does not contain the factory screen or diagnostics connections. I removed the factory screen and installed an Alpine TME-S370 Touchscreen in its place, leaving only the motor that raises and lowers the screen. The TME-S370 does have an AUX input, so it would be possible to connect a system such as the HKS Camp2 to display Diagnostic information.