multiple data sets

A large part of the problem is that i dont know the correct vocabulary. i
dont think multiple data sets is the correct phrase, so even if you cant
help with the problem - the correct phrase for what im trying to do may help
me search for my own answers.

I'm trying to work out how to get mutliple data sets to work, the wsdl
requires...

[..]
<OrderItemDetailsList>
         <OrderItemDetail>
           <ProductID>string</ProductID>
           <QuantityOrdered>int</QuantityOrdered>
         <OrderItemDetail>
           <ProductID>string</ProductID>
           <QuantityOrdered>int</QuantityOrdered>
         </OrderItemDetail>
</OrderItemDetailsList>
[..]

so normally i'd use something like

$client = new SoapClient($wsdl,$options);
$method = "DoSomething";
$params = new stdClass;

$params->OrderItemDetailsList->OrderItemDetail->ProductID = 1;
$params->OrderItemDetailsList->OrderItemDetail->QuantityOrdered = 2;

but obviously when i add the second set of data, it just overwrites the
first, i'm sure there must be away round this, but i just cant see it.


wsdl
http://213.123.43.101:8078/helixsopext.asmx?WSDL
method description
http://213.123.43.101:8078/helixsopext.asmx?op=OrderProcessAllClientProdID


--
Regards
Derek Almond
http://www.derekalmond.com