In Flex, how do I display "midi-channel" to s:Label?

I tried songTitle.text = mainXML.child("movement-title").text(); it worked but unsure how to display for midi-channel part.

<score-partwise>
  <movement-title>zsdf</movement-title>

  <part-list>
    <score-part id="P1">
      <part-name>Piano</part-name>

      <score-instrument id="P1-I1">
        <instrument-name>Acoustic Grand Piano</instrument-name>
      </score-instrument>

       <midi-instrument id="P1-I1">
        <midi-channel>1</midi-channel>
        <midi-program>1</midi-program>
      </midi-instrument>

    </score-part>
  </part-list>