I believe the 3225 uses VIA Unichrome graphics. You might want to look at the Averatec forum
http://www.averatecforums.com. I have Etch installed on my Averatec 3250. Etch uses Xorg and not XFree86 which is standard in Sarge. This is my xorg.conf which might get you started since the config files are similar.
Section "Files"
FontPath "unix/:7100" # local font server
# if the local font server has problems, we can fall back on these
FontPath "/usr/lib/X11/fonts/misc"
FontPath "/usr/lib/X11/fonts/cyrillic"
FontPath "/usr/lib/X11/fonts/100dpi/:unscaled"
FontPath "/usr/lib/X11/fonts/75dpi/:unscaled"
FontPath "/usr/lib/X11/fonts/Type1"
FontPath "/usr/lib/X11/fonts/CID"
FontPath "/usr/lib/X11/fonts/100dpi"
FontPath "/usr/lib/X11/fonts/75dpi"
EndSection
Section "Module"
Load "bitmap"
Load "dbe"
Load "ddc"
Load "dri"
Load "evdev"
Load "extmod"
Load "freetype"
Load "glx"
Load "int10"
Load "record"
Load "type1"
Load "vbe"
EndSection
Section "InputDevice"
Identifier "Generic Keyboard"
Driver "keyboard"
Option "CoreKeyboard"
Option "XkbRules" "xorg"
Option "XkbModel" "pc104"
Option "XkbLayout" "us"
EndSection
Section "InputDevice"
Identifier "Configured Mouse"
Driver "mouse"
Option "CorePointer"
Option "Device" "/dev/input/mice"
Option "Protocol" "ImPS/2"
Option "Emulate3Buttons" "true"
Option "ZAxisMapping" "4 5"
EndSection
Section "InputDevice"
Identifier "Synaptics Touchpad"
Driver "synaptics"
Option "SendCoreEvents" "true"
Option "Device" "/dev/psaux"
Option "Protocol" "auto-dev"
Option "HorizScrollDelta" "0"
Option "MaxSpeed" "0.12"
Option "MinSpeed" "0.06"
Option "BottomEdge" "4200"
Option "SHMConfig" "on"
Option "LeftEdge" "1700"
Option "FingerLow" "25"
Option "MaxTapTime" "180"
Option "MaxTapMove" "220"
Option "FingerHigh" "30"
Option "VertScrollDelta" "100"
Option "TopEdge" "1700"
Option "RightEdge" "5300"
Option "AccelFactor" "0.0010"
EndSection
Section "Device"
Identifier "VIA Technologies, Inc. VT8378 [S3 UniChrome] Integrated Video"
Driver "via"
Option "Disable IRQ"
Option "EnableAGPDMA"
EndSection
Section "Monitor"
Identifier "Generic Monitor"
ModelName "Flat Panel 1024x768"
HorizSync 31.5-48.5
VertRefresh 40-70
Option "DPMS"
EndSection
Section "Screen"
Identifier "Default Screen"
Device "VIA Technologies, Inc. VT8378 [S3 UniChrome] Integrated Video"
Monitor "Generic Monitor"
DefaultDepth 24
SubSection "Display"
Depth 1
Modes "1024x768"
EndSubSection
SubSection "Display"
Depth 4
Modes "1024x768"
EndSubSection
SubSection "Display"
Depth 8
Modes "1024x768"
EndSubSection
SubSection "Display"
Depth 15
Modes "1024x768"
EndSubSection
SubSection "Display"
Depth 16
Modes "1024x768"
EndSubSection
SubSection "Display"
Depth 24
Modes "1024x768"
EndSubSection
EndSection
Section "ServerLayout"
Identifier "Default Layout"
Screen "Default Screen"
InputDevice "Generic Keyboard"
InputDevice "Configured Mouse"
InputDevice "Synaptics Touchpad"
EndSection
Section "DRI"
Mode 0666
EndSection