In JIRA 5.0 the CSV import (external system import) does not allow me to map a field in my CSV file to a Multi User Picker field. It simply isn't an option. Nor is Multi User Picker field an option if I want the import to create a new custom field.
JIRA Importers Plugin versions prior to 4.1.3 had this option. It seems to be missing now.
Is there any way to import into a Multi User Picker field from a CSV file using the external system import?