xml from ajax to flex

how can i write an code in flex that generate an polyline from an xml file with an code like this :

<item><geo:line>45.359512625649,29.150035858154297
45.36917698955245,29.142783164978027
</geo:line><linecolor>black</linecolor><linewidth>8</linewidth><linealpha>0.7</linealpha><ymaps:GroupId>line1</ymaps:GroupId><description>descr</description></item>

the code in ajax was map.addOverlay(new YGeoRSS('sample.xml'));