Apologies for the English. We are currently working on development for FMK interfaces, and have so far been unable to find documentation on one of the fields which is used with quite a few of the message types. Specifically, the ModificationMetadata element is present in the schema for many of the data types, (CreateDrugMedicationType, CreatePrescriptionMedicationType, WithdrawDrugMedicationType, etc.) but we've been unable to find more information on how it should be used. Is there a preferred usage of this field?