My code:
public function beforeActivate(){
$event = $this->event;
$this->createParticipant();
}

public function createParticipant() {
$uuid = Participant::model()->gen_uuid();
$aData = array(
'participant_id' => $uuid,
'firstname' => 'Max1',
'lastname' => 'Muster1',
'email' => 'email@wdede.de',
'language' => 'en',
'blacklisted' => '',
'owner_uid' => 1,
'created_by' => 1
);
Participant::model()->insertParticipant($aData);
}