Configuring Virtual Resolution for XFree86 4.0

I have just upgraded my XFree86 from 3.3.5 to 4.0.
I am having some difficulty getting it to recognize Virtual resolution.
After reading the XF86Config man page, and applying some of the settings,
I have come to a dead end. I am using Slackware 4.0 on a system with a Voodoo
2000 AGP card. All was working fine with 3.3.5, and (after reading Readme's,
etc) the drivers are supposed to work the same for both versions, this is
perplexing.

Any ideas? Thanks in advance.

P.S. Here is my new XF86Config file

Section "ServerLayout"
    Identifier     "XFree86 Configured"
    Screen      0  "Screen0" 0 0
    InputDevice    "Mouse0" "CorePointer"
    InputDevice    "Keyboard0" "CoreKeyboard"
EndSection

Section "Files"
EndSection

Section "Module"
    Load  "extmod"
    Load  "xie"
    Load  "pex5"
    Load  "glx"
    Load  "dri"
    Load  "GLcore"
    Load  "dbe"
    Load  "record"
EndSection

Section "InputDevice"
    Identifier  "Keyboard0"
    Driver      "keyboard"
EndSection

Section "InputDevice"
    Identifier  "Mouse0"
    Driver      "mouse"
    Option      "Protocol" "PS/2"
    Option      "Device" "/dev/mouse"
EndSection

Section "Monitor"
    Identifier   "Monitor0"
    VendorName   "Monitor Vendor"
    ModelName    "Monitor Model"
EndSection

Section "Device"
    Identifier  "3Dfx Interactive Voodoo3"
    Driver      "tdfx"
    VendorName  "3Dfx Interactive"
    BoardName   "Voodoo3"
    BusID       "PCI:1:0:0"
EndSection

Section "Screen"
    Identifier "Screen0"
    Device     "3Dfx Interactive Voodoo3"
    Monitor    "Monitor0"
        DefaultDepth 24
    SubSection "Display"
        Depth     1
    EndSubSection
    SubSection "Display"
        Depth     4
    EndSubSection
    SubSection "Display"
        Depth     8
    EndSubSection
    SubSection "Display"
        Depth     15
    EndSubSection
    SubSection "Display"
        Depth     16
    EndSubSection
    SubSection "Display"
        Depth     24
                Modes "640x480"
                Virtual 2400 2000
    EndSubSection
EndSection

Section "DRI"
EndSection




--
Rick Rosinski
http://www.rickrosinski.com
rick@rickrosinski.com