The File Naming dialog box is enhanced to support the Mirror and Copy commands.
File Naming Enhancements
The Application Options 
File tab File Naming Defaults dialog box now includes a Mirror & Copy tab where you can specify how Mirror & Copy create files and folders. For example, you can use these settings to keep the folder structure flat and completely eliminate the sub-directory. In addition, you can now configure the naming scheme using the Display Name and File Name options.
For more information, see To Customize the Mirror and Copy Folder Structure .