Intel Haswell with 3 Displays

[Daniel Tihanyi]

Hi,
I have a Notebook with and Intel Haswell CPU (i5, 4th gen.) and 2
external displays (both connected via DisplayPort, there is no extra
GPU). I would like to use only the 2 external displays with the
notebook lid closed. The xf86-video-intel driver is installed and it
works, but it only recongizes the "first" two displays and the first is
always the built-in one. I can configure these two displays from the
XFCE Control Panel, unfortunately the 3rd display is not present. If
it's possible, I would like to not use a static xorg.conf file because
sometimes I only use the notebooks built-in display only without any
other display connected.
I use 11.0-RELEASE-p3.
Output of xranrd (the 3rd display is connected, it doesn't show up):
% xrandr
Screen 0: minimum 320 x 200, current 1920 x 1200, maximum 8192 x 8192
eDP1 connected (normal left inverted right x axis y axis)
   1920x1080     60.05 +
   1400x1050     59.98  
   1280x1024     60.02  
   1280x960      60.00  
   1024x768      60.00  
   800x600       60.32    56.25  
   640x480       59.94  
HDMI1 disconnected (normal left inverted right x axis y axis)
DP1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
DP2 connected primary 1920x1200+0+0 (normal left inverted right x axis
y axis) 519mm x 324mm
   1920x1200     59.95*+
   2560x1024     60.00  
   1680x1050     59.95  
   1400x1050     59.98  
   1280x1024     60.02  
   1440x900      59.89  
   1280x960      60.00  
   1280x800      59.81  
   1280x720      59.97  
   1024x768      60.00  
   800x600       60.32    56.25  
   640x480       60.00 

Thank you very much in advance!