Ubuntu – ATI: Multiple Video Card / Monitor Setup — Need help getting it working

So I currently have a dual-ati video card setup on my laptop. A low-power one and a high power one.

In windows 7 the drivers switch video cards when on external vs internal power. Also one of the video cards contains an HDMI output which I would like to use as it lets me plug in my monitor.

So is there an easy way to configure this?

Video Cards:

• Radeon HD 4200 – Low power
• Radeon HD 5600 – High power (contains the HDMI output)

Potential acceptable solutions:

• Deactivate low power card and use high power only. Worse battery life but whatever. However I don't want this done in BIOS since I want the good behavior in windows when dual booting.
• Get low power card working without high power card BUT HDMI output needs to work so I can plug monitor in.

Some progress:

aticonfig --adapter=all --initial finds both adapters after restart. The problem is X cannot start. It goes to black screen and must be restarted.

aticonfig --list-adapters only shows one adapter in a working config. The undesirable

configuring the high power adapter leads to same x not loading as –adapter=all