I use TCppWebBrowser to POST data and receive the resulting page BUT if the result is XML this doesn't work ?

  if (!(!pCppWebBrowser->Busy && pOutputStrings && pCppWebBrowser->Document &&
          String(pCppWebBrowser->LocationURL) != String("about:blank") &&
          SUCCEEDED(pCppWebBrowser->Document->QueryInterface(
          IID_IHTMLDocument2, (LPVOID*)&HTMLDocument))))
   {
      BrowserStatus=BROWSER_NOT_READY;
   }
   else
   {


      // Following DOES NOT WORK in case the result is XML !????? Any idea why ??

      // Page has been loaded, now extract the content of the file
      if(SUCCEEDED(HTMLDocument->QueryInterface(IID_IPersistFile,(LPVOID*)&PersistFile)))
      {
         // Save the file content to a temporary file
         PersistFile->Save(WideString(TempFile),false);
         PersistFile->Release();
      }


     // OR ... another approach ...
     // WHICH ALSO doesn't work :


     IHTMLElement *HTMLBody = NULL;

        if(SUCCEEDED(HTMLDocument->get_body(&HTMLBody)) && HTMLBody)
        {
            BSTR HTMLSource;
            if(HTMLBody && SUCCEEDED(HTMLBody->get_outerHTML(&HTMLSource)))
            {
                TMemo *Memo = new TMemo(BrowserParentForm) ;
                Memo->Text = WideString(HTMLSource);
                Memo->Lines->SaveToFile(TempFile) ;

 .....


Above code works great if the data is html for instance but if the result is XML then Getting the body or persistfile fails ?

Any ideas ???