Hi,
a third approach:
Use this XPath expression
"/x:APIInterface/x:StoreSiteResponse/x:ReturnCode
The construct the XPath object as:
XPath xp = XPath.newInstance(xpath);
xp.addNamespace(Namespace.getNamespace("x", "http://......."));
Element e = (Element)xp.selectSingleNode(requestDoc);
/pmn