Can you try using a generic 1024x768 display setting for it? My Radius monitor wouldn't get picked up either on my main system, so I had to define the timings manually (no biggie, I have the manual) after I installed my nvidia drivers for my GF4. During a Red Hat install, you can pick out the monitor manually if you like, or leave it at the probed settings (mine showed up as "unprobed monitor"). I just picked a generic 1024x768 monitor and it worked fine until I could get the drivers setup after reboot.