GDataXML addchild

Question

I have an XML file. Root is called document. document has several elements and nodes. In the middle, there are n number of documentFile elements. documentFile has some nodes. I would like to add 0 or more documentFile elements right after the last occurrence of documentFile

So I have something like:

<document>
   <someTags>
   <documentFile>
     <someSubTags>
   <documentFile> 
     <someSubTags>
   <someMoreTags>
</document>

I have tried using the following code:

GDataXMLDocument *tabsTree = [[GDataXMLDocument alloc]initWithData:tabsTreeData
                                                          encoding:NSUTF8StringEncoding
                                                             error:nil];
GDataXMLElement *rootElement = [tabsTree rootElement];
[rootElement addObject:[self createGDataXMLElementForDocumentFile:tab]];

As expected, this adds documentFile element to the end of the XML.

I have also tried

  GDataXMLElement *rootElement = [tabsTree rootElement];
  GDataXMLElement *documentFile = (GDataXMLElement *) [rootElement
                                 elementsForName:kDocumentFile][0];
  [documentFile addChild:[self createGDataXMLElementForDocumentFile:tab]];

This adds the documentFile element as the child of the first occurrence of documentFile, which is not surprising either.