beforeSaveElement example

            $valueData['value'] = $this->prepareValue($elementData, $valueData['value']);

            $value = new Value();
            $value->setElement($element);
            $value->setShop($shop);
            $value->setValue($valueData['value']);
            $values[$shop->getId()] = $value;
        }

        $this->beforeSaveElement($elementData);

        $values = Shopware()->Events()->filter(
            'Shopware_Controllers_Backend_Config_Before_Save_Config_Element',
            $values,
            [
                'subject' => $this,
                'element' => $element,
            ]
        );

        $element->setValues(new ArrayCollection($values));