Special Sort order

Hi everybody, I4m having a problem here.

I would like to sort my XML in a different way.
I have this XML.

 <NLIST>
    <NITEM>
      <PNR>AN4</PNR>
    </NITEM>
     <NITEM>
      <PNR>A0B</PNR>
    </NITEM>
    <NITEM>
      <PNR>291300A</PNR>
    </NITEM>
    <NITEM>
      <PNR>CCR244SS-3-2</PNR>
    </NITEM>
    <NITEM>
      <PNR>7028590-901</PNR>
    </NITEM>
     <NITEM>
      <PNR>MS20995C20</PNR>
    </NITEM>
  </NLIST>

And I need to sort it in a ascendant order but I need that the letters
come first than numbers. Like this:
 <NLIST>
    <NITEM>
      <PNR>AN4</PNR>
    </NITEM>
     <NITEM>
      <PNR>A0B</PNR>
    </NITEM>
    <NITEM>
      <PNR>CCR244SS-3-2</PNR>
    </NITEM>
    <NITEM>
      <PNR>MS20995C20</PNR>
    </NITEM>
    <NITEM>
      <PNR>291300A</PNR>
    </NITEM>
    <NITEM>
      <PNR>7028590-901</PNR>
    </NITEM>
  </NLIST>

Is there a way to solve this?

Thanks

Alexandre