If you take a look to the WSDL you'll see that the
Create operation parameter must contain a
request element that points to the actual
Create object parameter (that you can send as you did with an associative array).
I must say that the WSDL is not very correct because the same element name, meaning
Create is used twice for a different définition. Once as
element, once as
To be clear, you have to do so with your actual code :
$return = $client->Create(array('request'=>$params)); and it should work.