Update

// To create a subscription, to an existing product, for an 
// existing customer, using an existing billing plan

$autobill = new AutoBill();
$account = new Account();
$product = new Product();
$billPlan = new BillingPlan();

// Identify a previously created product by your unique ID
$product->setMerchantProductId('12345');

// Identify a previously created billing plan by your unique ID
$billPlan->setMerchantBillingPlanId('bp12345');

// Identify a previously created account by your unique ID
// Assumption: Account already has a payment method attached to it
// which will be used by the AutoBill automatically

$account->setMerchantAccountId('acct12345');

$autobill->setAccount($account);

// AutoBills may have multiple products 
// each in an AutoBillItem as an array:

$item = new AutoBillItem();
$item->setIndex(0);

// set the Product in the AutoBillItem
$item->setProduct($product); 

// set the Product (AutoBillItem)
$response = $autobill->setItems(array($item)); 

$autobill->setBillingPlan($billPlan);
$autobill->set('ab-44822'); // your ID for the AutoBill
$autobill->setCurrency('USD');

$validate = true;
$fraudScore = 100 ; // do not want to do risk screening

$response = $autobill->update('putAutoBillInRetryCycleIfPaymentMethodIsValid', 
   $validate, $fraudScore, true, true);

if($response['returnCode'] == 200 && $response['created'] ) {
   print "AutoBill created with VID " 
         . $response['data']->autobill->getVID() . "\n";
   if ( $response['authStatus'] != null ) {
      $txnStatus = $response['authStatus'];
      log (" CVN return code: " 
         . $txnStatus->getCreditCardStatus()->getCvnCode() 
         . "AVS return code" 
         . $txnStatus->getCreditCardStatus()->getAvsCode() . "\n");
   }
}