XML : XML node cannot traced

A web-service returns a XML over SOAP and I am trying to parse it. However I cannot reach nodes. I trace XML at all but nodes are untraceable.

  <soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">      <soap:Body>          <SbDrsRprRspnse xmlns="http://tempuri.org/">              <SbDrsRprRslt>                  <SODSRprDt>                      <Aktiv>false</Aktiv>                      <Silindi>false</Silindi>                      <Sira>0</Sira>                      <Numara>IL1</Numara>                      <AdSoyad>Maksim Tsygalha</AdSoyad>                      <ToplamEtk>30</ToplamEtk>                      <TamamEtk>6</TamamEtk>                      <Durum>20</Durum>                      <Units>                          <SbOgrtDSUnitRDt>                              <Aktif>false</Aktif>                              <Silindi>false</Silindi>                              <UnitsAdi>Ünite 3</UnitsAdi>                              <EtkTop>30</EtkTop>                              <TamamEtk>6</TamamEtk>                              <Durum>20</Durum>                          </SbOgrtDSUnitRDt>                      </Units>                  </SODSRprDt>              </SbDrsRprRslt>          </SbDrsRprRspnse >      </soap:Body>  </soap:Envelope>    

I can trace(returnXML) and see all things above. But when I try trace(returnXML.children().children().children()) it shows nothing. Also ==null, ==undefined, ==" ", and =="" returns false. What am I doing wrong?