Step 1.  Create a folder on the desktop called scripts.

Step 2.  Create a script named “postinstall” and put it in the scripts folder on the Desktop.  

NOTE:  do not add .sh to your script name or it will fail.  Best practice is to use a plain text editor when creating scripts.  IE.. TextWrangler or pico in the CLI.

Step 3.  Run the following command.  Enter your administrator password when prompted.

sudo pkgbuild --identifier com.mypackage.com --nopayload --scripts /Users/work/Desktop/scripts /Users/work/Desktop/MyPayFree.pkg

Step 4.  The package will be created and saved to your desktop.