Rotating X.org Screens

I have three monitors connected to my workstation at work, two of which are rotated 90 degrees counterclockwise. I simply added the bold sections under the Monitor stanzas in /etc/X11/xorg.conf :

Section "Monitor"

    # HorizSync source: edid, VertRefresh source: edid
    Identifier     "Monitor0"
    VendorName     "Unknown"
    ModelName      "Samsung SyncMaster"
    HorizSync       30.0 - 81.0
    VertRefresh     56.0 - 75.0
    Option         "DPMS"
    Option        "Rotate" "CCW"
EndSection

Section "Monitor"   

    # HorizSync source: unknown, VertRefresh source: unknown
    Identifier     "Monitor1"
    VendorName     "Unknown"
    ModelName      "DELL E173FP"
    HorizSync       31.0 - 80.0
    VertRefresh     56.0 - 75.0
    Option         "DPMS"
EndSection

Section "Monitor"

    # HorizSync source: unknown, VertRefresh source: unknown
    Identifier     "Monitor2"
    VendorName     "Unknown"
    ModelName      "Samsung SyncMaster"
    HorizSync       30.0 - 81.0
    VertRefresh     56.0 - 75.0
    Option         "DPMS"
    Option        "Rotate" "CCW"
EndSection

(duncan@puck:~)$ rpm -q xorg-x11-server-Xorg
xorg-x11-server-Xorg-1.1.1-48.41.el5_2.1
(duncan@puck:~)$ cat /etc/redhat-release 
CentOS release 5.2 (Final)