Mine

#IDILIACFGDESC=ATI Open Source driver dual screen, VGA screen #1, need to be at right. Force resolution. This configuration may not permit dual-screen.
#
# Idilia xorg.conf config, dual screen via ati driver.
# 

Section "Monitor"
	Identifier	"Configured Monitor1"
	Option "PreferredMode" "1920x1200_60.00"
	Option "Enable" "true"
	Modeline "1920x1200_60.00"  193.16  1920 2048 2256 2592  1200 1201 1204 1242  -HSync +Vsync
EndSection

Section "Monitor"
        Identifier      "Configured Monitor2"
	Option "RightOf"  "Configured Monitor1"
	Option "PreferredMode" "1600x1200_60.00"
	Modeline "1600x1200_60.00"  160.96  1600 1704 1880 2160  1200 1201 1204 1242  -HSync +Vsync
	Option "Enable" "true"
EndSection

Section "Screen"
	Identifier	"Default Screen"
	Monitor		"Configured Monitor1"
	Device		"radeon1"

	SubSection "Display"
		Depth                24
		Modes                "1920x1200" "1600x1200" "1280x1024" "1024x768" "800x600" "640x480"
		Virtual              3200 1200 
	EndSubSection
EndSection

Section "Device"
        Identifier      "Radeon1"
        Driver          "radeon"
	Option          "monitor-DVI-0" "Configured Monitor1"
        Option          "monitor-VGA-0" "Configured Monitor2"
	Option "DRI" "false"
EndSection

Section "ServerLayout"
	Identifier	"Default Layout"
	Screen		"Default Screen"
EndSection