This trick works in all versions of Mandriva.

Create a file /etc/udev/rules.d/01-touchpad.rules containing the text

  ACTION=="add", SUBSYSTEM=="input", ID_CLASS="mouse", RUN+="/usr/bin/synclient TouchpadOff=1"
  ACTION=="remove", SUBSYSTEM=="input", ID_CLASS="mouse", RUN+="/usr/bin/synclient TouchpadOff=0"

No need to reboot or anything. It works straight away. You will need to have the synaptics package installed and the Option “SHMConfig” “on” in /etc/X11/xorg.conf

  Section "InputDevice"
  Identifier "SynapticsMouse1"
  Driver "synaptics"
  Option "SHMConfig" "on"

and in the Section “ServerLayout” insert the line

  InputDevice "SynapticsMouse1" "SendCoreEvents"

(Thanks to the ArchLinux Wiki for this tip)