public Header ToVefa() { PeppolDocumentTypeId documentTypeId = PeppolDocumentTypeId.ValueOf(this.DocumentTypeIdentifier.Identifier); return(Header.Of( this.SenderId, this.RecipientId, this.ProfileTypeIdentifier, this.DocumentTypeIdentifier, this.InstanceId == null ? InstanceIdentifier.GenerateUuid() : this.InstanceId.ToVefa(), InstanceType.Of( documentTypeId.RootNameSpace, documentTypeId.LocalName, documentTypeId.Version), this.CreationDateAndTime )); }