How to setup dual head?

Hi, I got this new job last week where I have to deal with my university's servers, mostly Solaris but also some Linux. The guys were kind enough set me up a Fedora machine before I moved into the office. But unfortunately they only installed the "Fedora Desktop", i.e. Gnome on it. One of my colleagues told me that they liked KDE 3.5 a lot, but after the KDE 4.0 disaster, nobody was using KDE on the company anymore (see the impacts of certain decisions!). Well, this is not my point. Anyway, I logged in to Gnome and I set up the dual head (spanned desktop) with their tool and it worked right away. Later on, I told my colleagues that KDE improved a lot since 4.0 and they should give a try to 4.3. For a demonstration I installed KDE on my machine. I logged in and the first thing to do was to setup the dual head. I opened System Settings and as soon as I clicked on the Display, X crashed and I was thrown out. It was really a bad experience for a demonstration (kind of like Bill Gates' WinME video). I logged back in and ran krandrtray. This one crashed X too. I clicked on whatever I can find regarding the desktop setup and I found that everything on KDE that is related to the X settings crashes X. I then had to spend 15 minutes to write an xorg.conf file from scratch to make the dual head work, while people were making comments in the lines of "this is why I don't like KDE"... :( So, what was my mistake? This box has an ATI card and has the open source radeon drivers (the proprietary drivers are not available on F-11). Should ATI users stick to F-10 if they want to use KDE, which has only 2 months of lifetime left? I really feel bad. I wanted to show people how cool KDE 4.3 was, but I couldn't. Orcan