trying to add customer as child of parent customer not working

@access

I've been trying to add a new customer to a parent customer using the 2012_2 endpoint.
The code below adds the customer, with the billing and shipping address I supply, but not as a child of the requested parent customer. When I look at the new customer in NetSuite, the Parent Company is empty.

Checking the PHPToolkit_2012_2 NetSuiteService.php carefully, I noticed that for class Customer,  lines 49689-93 define:
public $parent;
/**
  * @access public
  * @var string 
  */
Should this be    * @var RecordRef  instead??

while in the $paramtypesmap, line 50253 defines:
  "parent" => "RecordRef",

I used code as follows, pulling customer data from another MySQL database, with $netsuiteParentCompanyId set equal to the NetSuite internal ID of the parent customer: