I'm trying to retrieve the Upgraded URLs via the Adwords API, but all I'm gettings is NULL. I'm using the latest version of the client library (v201502)
Here's the code I'm using

```
    $adGroupAdService = $this->oGAW->GetService('AdGroupAdService', ADWORDS_VERSION);

    $selector = new Selector();
    $selector->fields = array('AdGroupId');

    // Create predicates.
    $selector->predicates[] =
        new Predicate('AdGroupId', 'IN', array($adGroupId));
    $selector->predicates[] =
        new Predicate('AdType', 'IN', array('TEXT_AD', 'DYNAMIC_SEARCH_AD'));

    // Create paging controls.
    $selector->paging = new Paging(0, AdWordsConstants::RECOMMENDED_PAGE_SIZE);

    $page = $adGroupAdService->get($selector);

```

And it returns this 

```
object(TextAd)[107]
  public 'headline' => string 'headline'
  public 'description1' => string 'description1' 
  public 'description2' => string 'description2'
  public 'id' => string '76813511440' (length=11)
  public 'url' => null
  public 'displayUrl' => string 'test.nl/test'
  public 'finalUrls' => null
  public 'finalMobileUrls' => null
  public 'finalAppUrls' => null
  public 'trackingUrlTemplate' => null
  public 'urlCustomParameters' => null
  public 'devicePreference' => null
  public 'AdType' => string 'TextAd' (length=6)
  private '_parameterMap' (Ad) => 
    array (size=1)
      'Ad.Type' => string 'AdType' (length=6)

```

What am I doing wrong?

Thanks!