Merging a string to XML

I am actually updating a Legacy application in VB 6.0 and I need to add an element to a XML declared as IXMLDOMElement. My XML object's content is actually as follows;

<ChoiceLists>
 <Test Default="*">
  <Choice Value="1" Description="Hours"/>
  <Choice Value="2" Description="Days"/>
 </Test>
</ChoiceLists>

And now I have a query which is already returning me a XML formatted result (as string), as

<Test2 Default="*">
  <Choice Value="276" Description="#276"/>
  <Choice Value="177" Description="#177"/>
  <Choice Value="0000" Description="#0000"/>
  <Choice Value="176" Description="#176"/>
</Test2>

which I need to integrate in my XML, that is in the root node <ChoiceLists>.

Can anyone tell me how do I add this string into my XML please? I've been trying the different functions of the IXMLDOMElement object but in vain.

Thanks