how can i make my external second display as main display for ubuntu? Im using the ATI Control Center (amdcccle) Seems there is no way to make this switch under the GUI

Section "ServerLayout"
    Identifier     "amdcccle Layout"
    Screen      0  "amdcccle-Screen[1]-0" 0 0
EndSection

Section "Files"
EndSection

Section "Module"
    Load  "glx"
EndSection

Section "ServerFlags"
    Option	    "Xinerama" "off"
EndSection

Section "Monitor"
    Identifier   "0-LCD"
    Option	    "VendorName" "ATI Proprietary Driver"
    Option	    "ModelName" "Generic Autodetecting Monitor"
    Option	    "DPMS" "true"
    Option	    "PreferredMode" "1366x768"
    Option	    "TargetRefresh" "60"
    Option	    "Position" "1680 0"
    Option	    "Rotate" "normal"
    Option	    "Disable" "false"
EndSection

Section "Monitor"
    Identifier   "0-CRT1"
    Option	    "VendorName" "ATI Proprietary Driver"
    Option	    "ModelName" "Generic Autodetecting Monitor"
    Option	    "DPMS" "true"
    Option	    "PreferredMode" "1680x1050"
    Option	    "TargetRefresh" "60"
    Option	    "Position" "0 0"
    Option	    "Rotate" "normal"
    Option	    "Disable" "false"
EndSection

Section "Device"
    Identifier  "Default Device"
    Driver      "fglrx"
EndSection

Section "Device"
    Identifier  "amdcccle-Device[1]-0"
    Driver      "fglrx"
    Option	    "Monitor-LCD" "0-LCD"
    Option	    "Monitor-CRT1" "0-CRT1"
    BusID       "PCI:1:5:0"
EndSection

Section "Device"
    Identifier  "amdcccle-Device[1]-1"
    Driver      "fglrx"
    Option	    "Monitor-LCD" "0-LCD"
    BusID       "PCI:1:5:0"
    Screen      1
EndSection

Section "Screen"
    Identifier "Default Screen"
    DefaultDepth     24
EndSection

Section "Screen"
    Identifier "amdcccle-Screen[1]-0"
    Device     "amdcccle-Device[1]-0"
    DefaultDepth     24
    SubSection "Display"
    	Viewport   0 0
    	Virtual   3046 3046
    	Depth     24
    EndSubSection
EndSection

Section "Screen"
    Identifier "amdcccle-Screen[1]-1"
    Device     "amdcccle-Device[1]-1"
    DefaultDepth     24
    SubSection "Display"
    	Viewport   0 0
    	Depth     24
    EndSubSection
EndSection