ATI Radeon 6550D

I want to be able to run 2 monitors using DVI connections

If I purchase a system with integrated ATI Radeon 6550D graphics and also have a video card fitted this means there will be 2 DVI sockets, one from the on-board graphics and one from the card.

Will this work or will the video card disable the on-board graphics.

what do I need to do to set it up if this is possible

Thanks