Section "InputDevice"
        Identifier      "Configured Mouse"
        Driver          "mouse"
        Option          "CorePointer"
        Option          "Device"                "/dev/input/mice"
        Option          "Protocol"              "ImPS/2"
        Option          "ZAxisMapping"          "4 5"
        Option          "Emulate3Buttons"       "true"
+       Option          "EmulateWheel"          "true"
+       Option          "EmulateWheelButton"    "2"
  EndSection