config {
    tx_extbase {
        persistence {
            classes {
                // extend extbase filereference with own subclass
                TYPO3\CMS\Extbase\Domain\Model\FileReference {
                    subclasses {
                        Tx_KochUtlity_FileReference = Koch\KochUtility\Domain\Model\FileReference
                    }
                }
                // map own subclass on table
                Koch\KochUtility\Domain\Model\FileReference {
                    mapping {
                        tableName = sys_file_reference
                    }
                }
        	}
        }
    }
}