Acer aspire 1360 wlmi & twin view under linux

My acer aspire 1360 is equipped with a geforce video card capable of handling multiple sceen at time: the laptop screen and the external monitor screen. Here is my xorg.conf file

# nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig:  version 1.0  (buildmeister@builder3)  Tue Nov 22 18:04:42 PST 2005

# /etc/X11/xorg.conf (xorg X Window System server configuration file)
#
# This file was generated by dexconf, the Debian X Configuration tool, using
# values from the debconf database.
#
# Edit this file with caution, and see the /etc/X11/xorg.conf manual page.
# (Type "man /etc/X11/xorg.conf" at the shell prompt.)
#
# This file is automatically updated on xserver-xorg package upgrades *only*
# if it has not been modified since the last upgrade of the xserver-xorg
# package.
#
# If you have edited this file but would like it to be automatically updated
# again, run the following commands:
#
#   cp /etc/X11/xorg.conf /etc/X11/xorg.conf.custom
#   sudo sh -c 'md5sum /etc/X11/xorg.conf >/var/lib/xfree86/xorg.conf.md5sum'
#   sudo dpkg-reconfigure xserver-xorg

Section "ServerLayout"
    Identifier     "Default Layout"
    Screen         "Default Screen" 0 0
    InputDevice    "Generic Keyboard"
    InputDevice    "Configured Mouse"
    InputDevice    "Synaptics Touchpad"
EndSection

Section "Files"
			# local font server
	# if the local font server has problems, we can fall back on these
        # paths to defoma fonts
    FontPath        "unix/:7100"
    FontPath        "/usr/lib/X11/fonts/misc"
    FontPath        "/usr/lib/X11/fonts/cyrillic"
    FontPath        "/usr/lib/X11/fonts/100dpi/:unscaled"
    FontPath        "/usr/lib/X11/fonts/75dpi/:unscaled"
    FontPath        "/usr/lib/X11/fonts/Type1"
    FontPath        "/usr/lib/X11/fonts/CID"
    FontPath        "/usr/lib/X11/fonts/100dpi"
    FontPath        "/usr/lib/X11/fonts/75dpi"
    FontPath        "/var/lib/defoma/x-ttcidfont-conf.d/dirs/TrueType"
    FontPath        "/var/lib/defoma/x-ttcidfont-conf.d/dirs/CID"
EndSection

Section "Module"
    Load           "bitmap"
    Load           "dbe"
    Load           "ddc"
	#Load	"dri"
    Load           "extmod"
    Load           "freetype"
    Load           "glx"
    Load           "int10"
    Load           "record"
    Load           "type1"
    Load           "vbe"
EndSection

Section "InputDevice"
    Identifier     "Generic Keyboard"
    Driver         "keyboard"
    Option         "CoreKeyboard"
    Option         "XkbRules" "xorg"
    Option         "XkbModel" "pc105"
    Option         "XkbLayout" "it"
EndSection

Section "InputDevice"
    Identifier     "Configured Mouse"
    Driver         "mouse"
    Option         "CorePointer"
    Option         "Device" "/dev/input/mice"
    Option         "Protocol" "ImPS/2"
    Option         "Emulate3Buttons" "true"
    Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"
    Identifier     "Synaptics Touchpad"
    Driver         "synaptics"
    Option         "SendCoreEvents" "true"
    Option         "Device" "/dev/psaux"
    Option         "Protocol" "auto-dev"
    Option         "HorizScrollDelta" "0"
EndSection

Section "Monitor"
    Identifier     "Monitor Generico"
    ModeLine       "1280x800" 80.4 1280 1320 1520 1640 800 802 804 842
    Option         "DPMS"
	#HorizSync	28-49
	#VertRefresh	43-72
EndSection

Section "Device"

	#Driver		"nvidia"
	#BusID		"PCI:1:0:0"
#Option "SecondMonitorVertRefresh" "0"
    Identifier     "NVIDIA Corporation NV34M [GeForce FX Go 5200]"
    Driver         "nvidia"
EndSection

Section "Screen"
    Identifier     "Default Screen"
    Device         "NVIDIA Corporation NV34M [GeForce FX Go 5200]"
    Monitor        "Monitor Generico"
    DefaultDepth    24
    Option         "NvAGP" "3"
    Option         "DigitalVibrance" "0"
    Option         "TransparentIndex" "0"
    Option         "CursorShadowAlpha" "64"
    Option         "CursorShadowXOffse" "4"
    Option         "CursorShadowYOffset" "2"
    Option         "Twinview" "TRUE"
    Option         "TwinViewOrientation" "RightOf"
#Option "SecondMonitorHorizSync" "0"
    Option         "MetaModes" "1280x1024 , 1280x800 ; 1024x768 , 1024x768"
    Option         "ConnectedMonitor" "CRT-0 , DFP-0"
    SubSection     "Display"

#		Modes		"1024x768"
        Depth       1
    EndSubSection
    SubSection     "Display"

#		Modes		"1024x768"
        Depth       4
    EndSubSection
    SubSection     "Display"

#		Modes		"1024x768"
        Depth       8
    EndSubSection
    SubSection     "Display"

#		Modes		"1024x768"
        Depth       15
    EndSubSection
    SubSection     "Display"

#		Modes		"1024x768"
        Depth       16
    EndSubSection
    SubSection     "Display"

#		Modes		"1024x768"
        Depth       24
    EndSubSection
EndSection