Some times is always good to know what features and how the SoapClient from PHP works. I have seen in the dZone from Zend a article discussing one little thing, why SoapClient returns one element array as a Stdandard Object. There are some that like and there plenty that doens’t.
Anyway the important thing about this is that this article explains, very well, what to do if you don’t want a object as a return from the SOAP server.
Anyway check the SOAP Structures in PHP Article. It has a great point of view of how SOAP Strucutres work on PHP and what to do if you want the result in different format.