The video control is easy. You simply tell Centrafuse in the settings to show all video on display 2. That way you dont have to worry not being able to use nav and what not.
i am not sure what that D-Sub port is for, or rather how it works. Usually if its for RCA video, it would be yellow. This one is orange so im not sure if its the same thing. Download the manual for the mobo and see what that port is exactly for.