Currently this is not possible. For visit-based studies you have these options for the unique dataset keys

  PTID (demographic)
  PTID, SequenceNum (clinical data often)
  PTID, SequenceNum, ExtraKey (assay data often)

If the SequenceNum field is not important, I would suggest creating a dummy visit called "Progress Notes", and use that visit for all the rows in that dataset. It would be nice if we provided for auto-filling that value, but we don't have that feature yet.

Matt