Here is the code to place xml file to particular destination .
[WebMethod]
[ScriptMethod(ResponseFormat = ResponseFormat.Xml)]
public XmlDataDocument GetList(string keyword1, string streetname, string lat, string lng, string radius)
{
XmlDataDocument xmlDoc= CreateXML( keyword1,streetname,lat,lng,radius);
xmlDoc.Save(@"D:\blockseek7-9-2010\Block3.xml");
return xmlDoc;
// can i save it to outputstream or buffer
}