Description:
------------
If you implement the Iterator interface on one of the classes that you use in the 
classmap that you pass to SoapClient::SoapClient(), it does not work. If you use 
foreach() on the object that implements the interface it just iterates of the 
properties of the object instead of using the custom iterator you implemented.

Test script:
---------------
Not a full working code since this requires a SOAP service, but this gives you the gist:

class Bar implements Iterator { /*...*/ }

$bar = $soapClient->someFunc() // say this is an object returned by a SOAP client call and was mapped to class Bar

foreach ($bar as $key => $value) {
  // Just iterates over each property
}

$baz = new Bar();

foreach ($baz as $key => $value) {
  // Works as expected
}

Expected result:
----------------
I expect the custom iterator to be used when I iterator over an object returned by 
the SOAPClient.

Actual result:
--------------
Custom iterator is ignored, I get just regular iteration over all properties of 
the class Bar.