Magento Form Block not rendered

I am trying to make a real grid based on a magento model.
Everything is working well on the read part, but the form to edit isnt rendered and i have no errors in logs.
I noticed that my _prepareForm function is never called, but I don't know why.

My form call in controller:

public function editAction()
{
    $this->_initAction();

    // Get id if available
    $id  = $this->getRequest()->getParam('contact_request_id');
    $model = Mage::getModel('aeschbach_booking/contactRequest');

    if ($id) {
        // Load record
        $model->load($id);

        // Check if record is loaded
        if (!$model->getId()) {
            Mage::getSingleton('adminhtml/session')->addError($this->__('This Contact Request no longer exists.'));
            $this->_redirect('*/*/');

            return;
        }
    }

    $this->_title($model->getId() ? $model->getName() : $this->__('New Contact Request'));

    $data = Mage::getSingleton('adminhtml/session')->getContactRequestData(true);
    if (!empty($data)) {
        $model->setData($data);
    }

    Mage::register('aeschbach_booking', $model);

    $this->_addBreadcrumb($id ? $this->__('Edit Contact Request') : $this->__('New Contact Request'), $id ? $this->__('Edit Contact Request') : $this->__('New Contact Request'));
    $block = $this->getLayout()->createBlock('aeschbach_booking/adminhtml_contactRequest_edit')->setData('action', $this->getUrl('*/*/save'));
    $this->getLayout()->getBlock('content')->append($block);

    $this->renderLayout();
} 

And my form :

class Whatever_Booking_Block_Adminhtml_ContactRequest_Edit_Form extends Mage_Adminhtml_Block_Widget_Form
{
    /**
     * Init class
     */
    public function _construct()
    {
        parent::_construct();
        $this->setId('aeschbach_booking_contactRequest_form');
        $this->setTitle($this->__('Contact Request Information'));
        //when i var dump here i see that my controller called this function
    }

    protected function _prepareForm()
    {
        var_dump('here');
        die; // this var dump is never reached
    }
}