SW4 migration - configuration issues

Hello, I try to migrate my plugin to SW4 and I have some issues on installation. I have a variable that I must set as config. The code is bellow (inside install() method): $form = $this->Form(); $form->setElement(‚text‘, ‚AAA‘, array( ‚label‘=>‚BBB‘, ‚value‘=>‚CCC‘, ‚scope‘=>\Shopware\Models\Config\Element::SCOPE_SHOP )); $form->save(); But nothing is displayed inside the plugin window. This was ok on previous SW version. Does anyone have any idea? Thanks