Magento API product_media.create fails with PEAR SOAP

I am trying to add an image to a product using magento's SOAP api and I can succesffully upload it using the standard SoapClient but it fails if I use the Pear SOAP_Client

Here is what I'm doing with SoapClient:

$image_data = array(
        'file' => array(
           'name' => 'test_image_name',
           'cont开发者_运维百科ent' => $content,
           'mime'    => 'image/jpeg'
       ),
        'label'    => 'test_image_label',
        'position' => 1,
        'types'    => '',
        'exclude'  => 0
    );
$client = new SoapClient($wsdl_url);
$session_id = $client->login($mg_user, $mg_key);
$magento_filename = $client->call($session_id, 'product_media.create', array(
            $sku,
            $image_data
    ));

And that will successfully add the image to the product.

But If I use SOAP_Client:

$client = new SOAP_Client($wsdl_url, true);
$session_id = $client->call(
    'login',
    array(
        'username'=>$mg_user,
        'apiKey'=> $mg_key
    )
);
$magento_filename = $client->call(
    'call',
    array(
        'sessionId'=>$session_id,
        'resourcePath'=>'product_media.create',
        'args'=>array(
            $sku,
            $image_data,
        )
    )
);

I get the SOAPFault: "Cannot use object of type stdClass as array"

But I am able to call catalog_product.info:

$info = $client->call(
    'call',
    array(
        'sessionId'=>$session_id,
        'resourcePath'=>'catalog_product.info',
        'args'=>array($sku)
    )
);

and that returns all the correct data with no errors.

What could be causing the difference?

---

My solution, which is really no solution at all, was to reconfigure and reinstall php with --enable-soap.

But it might not be a feasible resort for others with the problem depending on their hosting scenarios.

---

Do not use PEAR's SOAP package. It's outdated and was used before the PHP SoapClient was there.