Digital itemized sets
Currently it is impossible to create an itemized set of digital titles/representations/files as the option of Rep ID header is not recognized by the system.
The rule of thumb is that a set of a specific entity can be created by a unique identifier of that entity only, and the same should apply here - we wouldn't like to create a set of titles, using rep IDs. This is similar to Portfolio_id which can only create a set of portfolios or item_ids for items. I can suggest that you add "Representation Details"."IED" to the analytics report, change the column name to "PID" and then create a set.