Custom commands does not work for local files.

Hi, I want to create backups of many many files. I want a custom command that will take the highlighted file (in the local panel) make a local copy and prompt me for the new extension.

I have tried everything.
xcopy "^" "^" "!?what is the new extension?.cfh!"

nothing seems to work. I keep all my versions on local, that is where I make changes, I only promote to remote with the final copy.