Is it possible to create or send my own custom command to work on ftp server

Question

I am creating a Android client which successfully uploads a file to my ftp server. I am using ftp4j library and want to send my custom command like this. e.g

mycustomcommand is a kind of tcp command..

FTPClient client = new FTPClient();

    try {

        client.connect(FTP_HOST, 21);
        client.login(FTP_USER, FTP_PASS);
        client.setType(FTPClient.TYPE_BINARY);

        client.changeDirectory("/Test/Uploads/");

        client.upload(fileName, new MyTransferListener());

        /**
         * Need help in this
         */
        FTPReply reply = client.sendCustomCommand("mycustomcommand");
        Log.e(TAG,"reply="+reply.toString() );

    }

Is it possible to do so using ftp or may be I need to use some another method like sockets..?

I just want to perform the action on server side based on mycustomcommand like upload or delete or rename..