I'm trying to configure xorg.conf to correctly set the resolution of my screens. I'm using a matrox triplehead, so the monitor is a single 5040x1050 screen. Unfortunately, it's being incorrectly set to 3840x1024. Here is my xorg.conf:

# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings:  version 260.19.06  (buildd@yellow)  Mon Oct  4 15:59:51 UTC 2010

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0" 0 0
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
    Option         "Xinerama" "0"
EndSection

Section "Files"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol" "auto"
    Option         "Device" "/dev/psaux"
    Option         "Emulate3Buttons" "no"
    Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Keyboard0"
    Driver         "kbd"
EndSection

Section "Monitor"
    # HorizSync source: edid, VertRefresh source: edid
    Identifier     "Monitor0"
    VendorName     "Unknown"
    ModelName      "Matrox"
    HorizSync       31.5 - 80.0
    VertRefresh     57.0 - 75.0
    #Option         "DPMS"
    Modeline "5040x1050@60" 451.27 5040 5072 6784 6816 1050 1071 1081 1103
    #Modeline "5040x1050@59" 441.28 5040 5072 6744 6776 1050 1071 1081 1103
    #Modeline "5040x1050@57" 421.62 5040 5072 6672 6704 1050 1071 1081 1103
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "GeForce 9800 GTX+"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "TwinView" "0"
    Option         "metamodes" "5040x1050"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection