TYPO3.Flow

If you activate @HasLifecycleCallbacks in your model and build a @PrePersist function like the following one - it doesn't work (or I'm to stupid to get it work ;)

<?php
declare(ENCODING = 'utf-8');
namespace Test\Animals\Domain\Model;

/**
 * @scope prototype
 * @entity
 * @HasLifecycleCallbacks
 */
class AnimalOwner {

    [...] 

    /**
     * @PrePersist
     */
    public function beforePersist(){
    echo "I don't have a cat.";
    exit;
    }
}

Or is there something missing in my model code?