How Can I Set the Customization Script for all VMs in a vApp

Using the .ExtensionData method found here: http://communities.vmware.com/thread/392462?start=0&tstart=0 (Thanks alanrenouf)

I'm able to set some guest customization properties via PowerCLI. 

My question is how do I set the CustomizationScript value with a simple guest cust script?

Is there a way to store it in a $variable?

Sample script i'd like to set:

@echo off

if "%1%" == "precustomization" (

echo Do precustomization tasks

) else if "%1%" == "postcustomization" (

cmd /c schtasks.exe /change /TN "\Microsoft\Windows\Defrag\ScheduledDefrag" /Disable

)

Thanks for the help.