Yes that's what I did but for OrderDetail, somebody helped me and told me that I should create a new field in OrderDetail to get the value in the Back Office orders.
class OrderDetail extends OrderDetailCore { public $svgTemplate; public function __construct($id = null) { self::$definition['fields']['svgTemplate'] = [ 'type' => self::TYPE_HTML, 'required' => false ]; parent::__construct($id); } }