Thanks for your effort everything seem to be ok now. Just one last thing. The following is my current output.

<?xml version="1.0" encoding="utf-8"?>
<LINE Value="some_text">
  <status/>
  <FEATURES/>
  <File1_data>
    <ABC id="1">
    <Feature>
        <Number>im from file 1</Number>
        <Prefix>419</Prefix>
        <Alt>73924/</Alt>
    </Feature>
</ABC>
    <ABC id="2">
    <Feature>
        <Number>im from file 1</Number>
        <Prefix>826</Prefix>
        <Alt>27800</Alt>
    </Feature>
</ABC>
    <ABC id="3">
    <Feature>
        <Number>im from file 1</Number>
        <Prefix>827</Prefix>
        <Alt>26433</Alt>
    </Feature>
</ABC>
  </File1_data>
</LINE>
[download]

as you can see that </ABC> (copied from Files_1 as a node) is not aligned properly so I just would like to learn how I can create nested elements and close them properly.
I have seen lots of examples but nothing is nested in the way I need it. I have tried many times but not sure whats going on. Following is what I need to get.

<?xml version="1.0" encoding="utf-8"?>
<LINE Value="some text">
  <status/>
  <FEATURES>
    <File1_data>
       <ABC id="1">
         <Feature>
           <Number>im from file 1</Number>
           <Prefix>419</Prefix>
           <Alt>73924/</Alt>
         </Feature>
       </ABC>
      <ABC id="2">
       <Feature>
          <Number>im from file 1</Number>
          <Prefix>826</Prefix>
          <Alt>27800</Alt>
       </Feature>
      </ABC>
     <ABC id="3">
      <Feature>
         <Number>im from file 1</Number>
         <Prefix>827</Prefix>
         <Alt>26433</Alt>
      </Feature>
     </ABC>
    </File1_data>
 </FEATURES>
</LINE>
[download]

sorry for asking to much but any idea if I can access the elements Im copying and modify its name?
for example lets say I would like to add numbers to the Features elements im copying i.e <Feature 1> <Feature 2>....etc.