Don't know about Excel, but in Word, while you can copy the button control itself, as you have discovered, the code does NOT come along with it. This is a function of SCOPE. Code in form modules (as opposed to standard or class modules) are PRIVATE to that form module - as long as the other form module is in the same project...which it is.
You can export the form module to another project, rename it and import it back into the first project.
Gerry