I don’t know why this was so hard. Lots of hacks out there for getting dual head working on an ATI Radeon. This is an X1300.
I started up and Ubuntu detected that there was a Radeon installed and the restricted drivers manager wanted to install the fglrx (ati) drivers. I did this and rebooted, then ran this command with a fairly clean xorg.conf:
aticonfig –initial=dual-head –dtop=horizontal