Dell inspiron 4000 + Docking Station + Dual display

I’m trying to get a Dell Inspiron 4000 with ATI Rage Pro Mobility Grafic Card and a Dell Docking station to work with an external Monitor in Xinerama mode working, using OpenSUSE 11.1 (KDE4). The problem is that with SAX2 I only see the internal display, or if I install SUSE with the external display attached, SAX only sees the external display, but once X starts up it only displays on the internal monitor.

Is there a way to get the 2nd monitor working?