There may be a way to create the text file straight out to the FTP server in one command but I have not seen it "yet".
What I have had to do is create my Source connection as the DB and my destination connection as the text file. The location of the text file is place in the folder on my local FTP server.
I then create my data pump to pull the records from the DB and place them in my text file. Once that is complete, I create an FTP task that send the file from my local FTP share to the destination FTP server.
You could also use a WIN32 task, then set it up as an FTP task and have then use a connection file( text file) that has the info to log onto the remote FTP server and "puts" the file.
Thanks
J. Kusch