Ha ha, the sany bridge boards support chips with built in gpu. It's not like you can peel the chip open and take parts out.
That was going to be my suggestion.
greg is right though. The motherboard will detect the presence of the graphics card and automatically deactivate the built in graphics.
I recommend that you do not use the BIOS to turn off the built in graphics. That way, if you ever need to pull the video card, you will not need to do anything but move the monitor cable to the motherboard connector.