xfce-4.1.91 & Virtual screen

[VnPenguin]

Hi,
In Xorg config of my FC2 box, I have:
--------------------------------------------------------
Section "Screen"
   Identifier "Screen0"
   Device     "Videocard0"
   Monitor    "Monitor0"
   DefaultDepth     24
   SubSection "Display"
       Viewport   0 0
       Depth     24
       Modes    "1152x864" "1024x768" "800x600" "640x480"
       Virtual 1600 1200
   EndSubSection
EndSection
----------------------------------------------------------
When I run Xfce-4.1.91 I loss my Virtual screen 1600x1200.
With old version of Xfce (4.0.x), there is no such problem.

Any idea for fix this problem?

TIA,

-- 
http://vnoss.org/forum/