Does the script do more than what a built-in command like this does?
FileType NEW=.txt NEWNAME="Untitled.tsl"
That will create a new empty file called "Untitled.tsl" and let you type a new name for it.
If the script does more, it might be worth detailing some of what it does and reasons to use it instead of the more simple built-in command.
(For the built-in command, there's more detail at How to Create New/Empty Files.)
When in Customize mode, you can drag buttons or menus to a folder to create XML versions of them for sharing as files, or right-click them and use Copy to create XML versions of them in the clipboard for sharing as text. Both can be dragged or pasted back to the toolbars in a similar way.