Add more flexibility with renaming files

Although I appreciate the new live view function and the renaming option I still would like to have more flexibility when renaming files.
I just wish in the renaming I could eliminate the hyphen ("-001") and use an underscore ("_001"). With complicated filenames the readability of an underscore is much better.

Of course I could rename it on my desktop but then it would be different on the iPad, the camera card and the desktop. And that is not a good temporary backup solution until the final backups are done.