Getting Systemuser & related entity fields

//----------------------------------------------------------
getSystemUserInformation = function() {
//----------------------------------------------------------
var f = crmForm.all;
//setup some vars to use in constructing the formula and storing the values
var entityForList = 'systemuser';
var attribForFilter = 'systemuserid' ;
var idToFetch = f.ownerid.DataValue[0].id+ '' ;
var attribToReturn = 'mobilephone';
var attribToRtn2 = 'new_departmentid';

var xml = "" +
"" +
"http://schemas.xmlsoap.org/soap/envelope/\" xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\">" +
" " +
" http://schemas.microsoft.com/crm/2006/Query\" xsi:type=\"q1:QueryExpression\" xmlns=\"http://schemas.microsoft.com/crm/2006/WebServices\">" +
" " + entityForList + "" +
" " +
" " +
" " + attribToReturn + "" +
" " + attribToRtn2 + "" +
" " +
" " +
" true" +
" " +
" And" +
" " +
" " +
" " + attribForFilter + "" +
" Equal" + " " +
" " + idToFetch + "" +
" " +
" " +
" " +
" " +
" " +
" " +
"" +
"";

var xmlHttpRequest = new ActiveXObject("Msxml2.XMLHTTP"); xmlHttpRequest.Open("POST", "/mscrmservices/2006/CrmService.asmx", false); xmlHttpRequest.setRequestHeader("SOAPAction","http://schemas.microsoft.com/crm/2006/WebServices/RetrieveMultiple"); xmlHttpRequest.setRequestHeader("Content-Type", "text/xml; charset=utf-8"); xmlHttpRequest.setRequestHeader("Content-Length", xml.length); xmlHttpRequest.send(xml);
var resultXml = xmlHttpRequest.responseXML;
//alert( resultXml.xml )

if ( resultXml.selectSingleNode("//mobilephone") != null ) {
var tempText = resultXml.selectSingleNode("//mobilephone").text;
f.new_mobilephone.DataValue = tempText;
f.new_mobilephone.ForceSubmit=true;
}

if ( resultXml.selectSingleNode("//new_departmentid") != null ) {
f.new_departmentid.DataValue = setlookupValue( resultXml.selectSingleNode("//new_departmentid").text,
resultXml.selectSingleNode("//new_departmentid/@name").text,
'new_department' ) ; }
};