public function getSoapVariables($requestObject, $lowerCaseFirst = false, $keepNullProperties = true)
    {
        if (!is_object($requestObject)) {
            throw new InvalidParameterException('Parameter requestObject is not an object');
        }
        $objectName = $this->getClassNameWithoutNamespaces($requestObject);
        if ($lowerCaseFirst) {
            $objectName = lcfirst($objectName);
        }
        $stdClass = new \stdClass();
        $stdClass->$objectName = $requestObject;

        return $this->objectToArray($stdClass, $keepNullProperties);
    }