I have a 24" iMac that I'd like to add a second display to - specifically, the Apple 23" Cinema HD Display. I understand that I'll need the mini-DVI to DVI adapter to connect it. My question is this - will it work in dual-display mode? The official tech specs say that only video mirroring is supported, but I searched these forums and have heard reports of people getting dual displays on various Intel iMacs to work out of the box. I'm confused.