Use xinput command to find the trackpoint device name

$ xinput

Create file /etc/X11/xorg.conf.d/10-thinkpad-trackpad-scroll.conf with following content.

Note: The string after MatchProduct should be the trackpoint device name found in previous step.

Section "InputClass"
    Identifier  "Trackpoint Wheel Emulation"
    MatchProduct    "TPPS/2 IBM TrackPoint"
    MatchDevicePath "/dev/input/event*"
    Option      "EmulateWheel"      "true"
    Option      "EmulateWheelButton"    "2"
    Option      "Emulate3Buttons"   "false"
    Option      "XAxisMapping"      "6 7"
    Option      "YAxisMapping"      "4 5"
EndSection

Restart your computer

Reference: - http://www.thinkwiki.org/wiki/How_to_configure_the_TrackPoint#xorg.conf.d - http://forums.fedoraforum.org/showthread.php?t=280930