This may be a slight repost of my previous question (http://ubuntuforums.org/showthread.php?t=2093087), but my question is a bit different this time.

So as I mentioned before, I have 2 graphics cards: an ATI Radeon HD 5770 and an NVIDIA Geforce GTX 550Ti, connected to 3 monitors. The NVIDIA card has output going through 2 DVI ports, while the ATI card only has an HDMI output. My issue is that I can't get both cards to work at one.

Previously I thought this was because the devices had different drivers, but then realized that shouldn't be a problem, especially if X's configuration files still list both cards. Now I suspect X to just not be configured correctly. Now, after some searching it seems that
Code:
X -configure
is deprecated and should not be use, but then how should I go about configuring X?

As a final note, running xrandr only lists screen 0 (both the DVI monitors) and the connections from the nvidia card. My final goal would be to include the ATI's HDMI display on the same "screen", but configuring each to be a separate X screen would also be acceptable.

Also, I doubt that it matters, but the DVI outputs are 1680x1050 monitors and the HDMI output is a 720p TV.