Please refer to the FTP section.

To configure FTP over SSL, choose FTP Listener from the Listener Type drop down.
Basic tab – here you can set the FTP Type: Encrypted FTP (SSH/SFTP), Regular FTP or FTP over SSL (Explicit or Implicit). Set FTP over SSL (Explicit or Implicit).

In the FTP over SSL there is also a Data Channel Protection Level drop down which will allow you to provide the SSL security mode of either Private or Clear.