It seems in my XF86Config, only 1 entry works, either the built-in mouse,
or the USB mouse. Even if I added both entries in, only one entry
works... Is there any way to make both of them work?

I'm using SuSE 7.3, and XFree86 v4.1.0.

Thanks!

Section "InputDevice"
Identifier "PS Mouse"
Driver "mouse"
Option "CorePointer"
Option "Device" "/dev/psaux"
Option "Protocol" "ImPS/2"
Option "Emulate3Buttons" "no"
# Option "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"
Identifier "USB Mouse"
Driver "mouse"
Option "Device" "/dev/input/mice"
Option "Protocol" "ImPS/2"
Option "Emulate3Buttons" "no"
Option "ZAxisMapping" "4 5"
EndSection

Note also the 'Option "CorePointer"' line.

Under the Layout section:

Section "ServerLayout"
Identifier "Default Layout"
Screen "Default Screen"
InputDevice "Generic Keyboard"
InputDevice "PS Mouse"
InputDevice "USB Mouse" "SendCoreEvents"
EndSection

Cheers,