After hacking fglrx in the system, and creating a custom xorg.conf with dpkg-reconfigure, finally I got in to the launch manager.
After a while, I got a screen which said 'One moment', and after that the setup screen. (If you can see and hear me, press the Next button, or so) Now the problem:
There was no video (don't know if that's normal), clicking anywhere does not do anything, pressing a button on the keyboard also, and on the remote too. Every while, the screen blinked to black for a second. Direct rendering is enabled, and I'm using UI2 without alpha blending.
My video card is an ATI Radeon X300 with 128MB RAM, which once ran Pluto correctly with UI2 with no alpha blending.