php - SOAP APIを介してmagentoでカスタム属性の値を取得する方法

Question

SOAP API を使用して、magento 製品のカスタム属性の値を取得しようとしています。しかし、標準の属性値しか取得できません。以下のコードを試していますが、うまくいかないようです。

$user = 'user';
$password = 'pass';
$proxy = new SoapClient('http://asd.com.au/api/v2_soap?wsdl');
$sessionId = $proxy->login($user, $password);

   //method 1 I tried
    $ebayStock = new stdClass();
    $ebayStock->key = 'ebay_available_qty';
    $additionalAttributes['single_data'][] = $ebayStock ;
    $ebay = $proxy->catalogProductInfo($sessionId, $sku,1,$additionalAttributes);
    var_dump($ebay);

//出力

   object(stdClass)[4]
  public 'product_id' => string '3230' (length=4)
  public 'sku' => string 'test101' (length=7)
  public 'set' => string '9' (length=1)
  public 'type' => string 'simple' (length=6)
  public 'categories' => 
    array (size=0)
      empty
  public 'websites' => 
    array (size=1)
      0 => string '1' (length=1)
  public 'created_at' => string '2013-05-12 23:07:33' (length=19)
  public 'updated_at' => string '2013-05-13 04:54:50' (length=19)
  public 'type_id' => string 'simple' (length=6)
  public 'name' => string 'test' (length=4)
  public 'description' => string 'asd' (length=3)
  public 'short_description' => string 'asd' (length=3)
  public 'weight' => string '123.0000' (length=8)
  public 'status' => string '1' (length=1)
  public 'url_key' => string 'test' (length=4)
  public 'url_path' => string 'test.html' (length=9)
  public 'visibility' => string '3' (length=1)
  public 'category_ids' => 
    array (size=0)
      empty
  public 'has_options' => string '0' (length=1)
  public 'price' => string '11.0000' (length=7)
  public 'tax_class_id' => string '0' (length=1)
  public 'tier_price' => 
    array (size=0)
      empty
  public 'options_container' => string 'container2' (length=10)
  public 'enable_googlecheckout' => string '1' (length=1)

Method 2 I tried.

$ebay = $proxy->catalogProductInfo($sessionId, $sku,1,array('ebay_available_qty'));
var_dump($ebay);

//gives same output

属性「ebay_available_qty」の値を取得しようとしています。

よろしくアブナブ