You could add a Script Task to the FeLC before the FTP Task and send the variable holding the file name in as a ReadOnlyVariable. In the Script Task fire an information event (see below) to send the file name to the output. Just make sure you are logging the output of the SSIS package execution to a file or table.
Dim tempBool As Boolean = false
Dts.Events.FireInformation(1, "File Name", Dts.Variables("User::FileName").Value.ToString(), "", 0, tempBool)
You could achieve the same by having the variable that holds the file names raise an event whenever its value changes and implementing an Event Handler for that event to also raise an information event so it appears in the log. Same result, you just wouldn't see the Script Task in the Control Flow, it would be tucked away in an Event Handler.
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