Unmanned unit dispatched by CAD (has no personnel associated)

Once sufficient personnel arrive at the fire station, the unit marks themselves En Route on MPS.

A pop-up window presents to the MPS user with entry form to log the number of qualified personnel on board.

The number is written to the database along with the En Route status, presenting in un_hi as a single row.

The solution has to allow for easy reporting on the number of personnel on each unit assigned to an event. I have handled the forms (currently just writing a unit history comment), and can handle all the activity in getting the information into the Event Reports.  The part I don't know how to handle is getting the custom fields updated with the ER command.   A similar topic posted recently which was writing to cd_units, but was not associated with a status change and not recorded to the un_hi specifically.  The post also did not detail how it was accomplished unfortunately.