Region Code missing in SAP Marketing Cloud

Hi all,

what to do if there's a RegionCode for a Country that comes e.g. from C4C and in SAP Marketing Cloud that Region does not exist for the Country?

Import Monitor says "Region Code is not valid".

It is not possible to do a Freetext Mapping or to upload the new Region for the Country.

How to proceed? Until now we always had all the needed Regions for all of the Countries we used and I'm not sure if I oversee something. How to add a new Region for a Country in SAP Marketing Cloud?