Creating Menus in FileMaker

Hello to all, I am new to AppleScript, I am experimenting with the AppleScripting of Filemaker and I just developed the next script:

tell application “FileMaker Developer”
create new menu item with properties “Mymenu” at menu “External”
end tell

This script adds a new menu called “Mymenu” in the script menu, it looks ok, I can select it fine but I cant make this menu to do anything! how can I link this new menu to a script or applescript??? how can I make it work???

I hope someone can help me out!

Thank you!

Brian Donovan