NXSD define trailing optional columns
I am trying to read a csv file in Oracle Integration Cloud (OIC). OIC accepts an xsd file to define the format for the inbound csv file. The issue I'm having is that the csv file can have optional columns, and I can't figure out how to define this in NXSD.
I can define an xsd to say the csv to have 5 cols or 3 cols. But how do I provide a single xsd to say the first 3 cols are to be expected (mandatory) and cols 4 & 5 may or may not be available?
I am also told that SOA Suite has a "Native Format Builder Wizard" that can do this, but I do not have access to this. Can someone please help?