Adding Item Grouping as an Line Item in the Item List?

Hello,

I'm looking to add a item grouping in the itemList similar to how I would add an item.  When I try to use the item grouping internal id I am flagged with an error that states that I need at least one item in the list to continue.  Check out the soap:

<add xmlns="urn:messages_2_0.platform.webservices.netsuite.com">  <record xsi:type="ns8:SalesOrder" xmlns:ns8="urn:sales_2_0.transactions.webservices.netsuite.com">  <ns8:customForm internalId="100" xsi:type="ns9:RecordRef" xmlns:ns9="urn:core_2_0.platform.webservices.netsuite.com" />   <ns8:entity internalId="1034" xsi:type="ns10:RecordRef" xmlns:ns10="urn:core_2_0.platform.webservices.netsuite.com" />   <ns8:orderStatus xsi:type="ns11:SalesOrderOrderStatus" xmlns:ns11="urn:types.sales_2_0.transactions.webservices.netsuite.com">_pendingFulfillment</ns8:orderStatus>   <ns8:memo xsi:type="xsd:string">Please also include a new metal kioskBoth metal and wood parts. thanks!</ns8:memo>   <ns8:location internalId="1" xsi:type="ns12:RecordRef" xmlns:ns12="urn:core_2_0.platform.webservices.netsuite.com" />   <ns8:itemList replaceAll="false" xsi:type="ns8:SalesOrderItemList"><ns8:item xsi:type="ns8:SalesOrderItem">     <ns8:item internalId="3774" xsi:type="ns13:RecordRef" xmlns:ns13="urn:core_2_0.platform.webservices.netsuite.com" />      <ns8:quantity xsi:type="xsd:double">1</ns8:quantity>     </ns8:item></ns8:itemList>   <ns8:customFieldList xsi:type="ns14:CustomFieldList" xmlns:ns14="urn:core_2_0.platform.webservices.netsuite.com">   <ns14:customField internalId="custbody_so_osc_number" xsi:type="ns14:LongCustomFieldRef">    <ns14:value xsi:type="xsd:long">4286</ns14:value>    </ns14:customField>  </ns8:customFieldList>  </record>  </add>