ethereal, first off, do you know how to add a menu item?
You have to enter customize mode, then you can right-click on menu items and select things such as "Insert New / New Button"
How do you enter customize mode? In my view the easiest is to enable this preference: in Preferences, type "customize" in the search box, then check the box that says "Alt-click to edit toolbar buttons".
After that, any time you alt-click a toolbar button or menu item or an empty space on a toolbar, you enter customize mode. Then you can right-click inside menus or on the toolbar to add buttons.
In your new button, to make a regex renamer, this is the syntax you paste in the function box
Rename PATTERN="your_search_regex" TO="your_replace_expression " FINDREP