Can't swap displays in xorg.conf

[Robert Cardell]

I've got a FireGL 8800 with a 21" monitor on the VGA port and a 17" on
the DVI port (through a DVI->VGA adaptor). I'm trying to set up dualhead
so that the 21" is my primary monitor and the 17" the secondary to the right.

I've tried just about every possible combination of swapping Screen options
and identifiers etc., and still the X server insists on making the DVI port
Screen 0 and the VGA port Screen 1. I can put "LeftOf" instead of "RightOf"
in the ServerLayout section, but that still means my programs and pointer
start on the 17", which is not what I want.

The reason I don't just swap connectors is that the VGA port on this card
has noticably better signal quality than the DVI port, and it makes a real
difference on the 21" screen.

Here's my xorg.conf (stripped down a bit for readability). Could someone
tell me what to change so the VGA port becomes the primary screen?
(BTW, the MonitorLayout option is needed because the 17" doesn't get detected.)

Section "ServerLayout"
    Identifier     "X.org Configured"
    Screen      0  "Screen0" 0 0
    Screen      1  "Screen1" RightOf "Screen0"
    InputDevice    "Mouse0" "CorePointer"
    InputDevice    "Keyboard0" "CoreKeyboard"
EndSection

Section "Files"
    RgbPath      "/usr/X11R6/lib/X11/rgb"
    ModulePath   "/usr/X11R6/lib/modules"
    FontPath     "/usr/X11R6/lib/X11/fonts/misc/"
    FontPath     "/usr/X11R6/lib/X11/fonts/TTF/"
#    FontPath     "/usr/X11R6/lib/X11/fonts/Speedo/"
    FontPath     "/usr/X11R6/lib/X11/fonts/Type1/"
#    FontPath     "/usr/X11R6/lib/X11/fonts/CID/"
    FontPath     "/usr/X11R6/lib/X11/fonts/75dpi/"
    FontPath     "/usr/X11R6/lib/X11/fonts/100dpi/"
EndSection

Section "Module"
#   Load  "record"
    Load  "extmod"
    Load  "dbe"
#    Load  "dri"
#    Load  "glx"
    Load  "xtrap"
    Load  "freetype"
    SubSection "extmod"
        Option  "omit xfree86-dga"
    EndSubSection
EndSection

Section "DRI"
    Mode 0666
EndSection

Section "InputDevice"
    Identifier "Keyboard0"
    Driver     "kbd"
    Option     "XkbRules" "xorg"
    Option     "XkbModel" "pc105"
    Option     "XkbLayout" "gb"
    Option     "AutoRepeat" "250 30"
EndSection

Section "InputDevice"
    Identifier  "Mouse0"
    Driver      "mouse"
    Option      "Protocol" "ImPS/2"
    Option      "Device" "/dev/misc/psaux"
    Option      "ZAxisMapping" "4 5"
EndSection

Section "Monitor"
    Identifier   "Monitor0"
    Option       "DPMS"
EndSection

Section "Monitor"
    Identifier   "Monitor1"
    Option       "DPMS"
EndSection

Section "Device"
    Identifier  "Card0"
    Driver      "radeon"
    VendorName  "ATI Technologies Inc"
    BoardName   "Radeon R200 QH [Radeon 8500]"
    BusID       "PCI:1:5:0"
    Option "MonitorLayout" "CRT,CRT"
    Screen 0
EndSection

Section "Device"
    Identifier "Card1"
    Driver "radeon"
    VendorName  "ATI Technologies Inc"
    BoardName   "Radeon R200 QH [Radeon 8500]"
    BusID "PCI:1:5:0"
    Option "MonitorLayout" "CRT,CRT"
    Screen 1
EndSection

Section "Screen"
    Identifier "Screen0"
    Device     "Card0"
    Monitor    "Monitor0"
    DefaultDepth 24
    DefaultFbBpp 32
    SubSection "Display"
        Depth     24
    EndSubSection
EndSection

Section "Screen"
    Identifier "Screen1"
    Device "Card1"
    Monitor "Monitor1"
    DefaultDepth 24
    DefaultFbBpp 32
    SubSection "Display"
        Depth     24
    EndSubSection
EndSection