You can add commands to run on the system immediately after the kickstart file has been parsed and before the installation begins. If you have configured the network in the kickstart file, the network is enabled before this section is processed. To include a pre-installation script, type it in the text area.
To specify a scripting language to use to execute the script, select the Use an interpreter option and enter the interpreter in the text box beside it. For example, /usr/bin/python2.2 can be specified for a Python script. This option corresponds to using %pre --interpreter /usr/bin/python2.2 in your kickstart file.
Do not include the %pre command. It will be added for you.