Es facil:
Código PHP:
$xml = new GeckoXML("playlist");
$track = $xml->createNode( "tracklist" );
$track1 = $track->createNode( "track" );
$title1 = $track1->createNode( "title" );
$title1->setData("Mil Horas");
$track1->appendChild( $title1 );
$creator1 = $track1->createNode("creator");
$creator1->setData("ABUELOS DE LA NADA");
$track1->appendChild($creator1);
$location1 = $track1->createNode("location");
$location1->setData("SPnoRFI7C6fO.rbs");
$track1->appendChild($location1);
$track->appendChild($track1);
$xml->appendChild($track);