Logitech Mouse 4 Way Scrollbutton.

For Logitech RX300:

Section "InputDevice"
Identifier "Configured Mouse"
Driver "evdev"
Option "Dev Name" "Logitech USB Optical Mouse"
Option "CorePointer"
Option "Device" "/dev/input/event2"
Option "Buttons" "7"
Option "ZAxisMapping" "4 5 6 7"
EndSection

ps: Information of Option "Device" comes from /proc/bus/input/devices

For Logitech RX1000:


Section "InputDevice"
Identifier "Configured Mouse"
Driver "evdev"
Option "Dev Name" "Logitech USB Optical Mouse"
Option "CorePointer"
Option "Buttons" "8"
Option "ZAxisMapping" "4 5 6 7"
Option "Resolution" "1000"
EndSection