Changing the About menu in an Applet

Is it possible in an AppleScript applet to change the content displayed in an applet’s about menu?

I’d like to add a typical About this App with copyright and disclaimer text.

Create a file named Credits.rtf with the content you want to display, and copy it into the applet’s Resouces folder. I think this also works with a file named Credits.html but haven’t tested it recently.

No joy.

Also tried with description file.

Works here: