You might want to keep an eye out for some new content that the Learning Services are planning on publishing soon.
Building Custom Business Services Course
This course will be updated for IRIS for Health and includes an FTP example that will include the Attributes property. If you check out the current offering, you'll see that it consumes a file called Appointments.txt from ftp.intersystems.com. See exercise in 3.5 (creation) and 4.3 (implementation). The video uses the File adapter, but the exercise uses FTP.
Hope this helps!