create annotation using javascript in microsoft crm 4.0

Using Microsoft CRM 4.0

I have a requirement to create a note automatically in a custom entity when an Email is sent from that entity. Am using javascript to do this, below is the code i have used, but is not working for note creation.

Please help.

    //get Authenication
    var authenticationHeader = GenerateAuthenticationHeader();

    // Prepare values for the note
    var notetext = "This is a sample note";
    var subject = "Test Subject";
    var objectId = crmForm.ObjectId;
    var objectTypeCode = "10003";

    // Prepare the SOAP message.
    var xml = "<?xml version='1.0' encoding='utf-8'?>" +
    "<soap:Envelope xmlns:soap='http://ift.tt/sVJIaE'" +
    " xmlns:xsi='http://ift.tt/ra1lAU'" +
    " xmlns:xsd='http://ift.tt/tphNwY'>" +
    authenticationHeader +
    "<soap:Body>" +
    "<Create xmlns='http://ift.tt/19Bb7BX'>" +
    "<entity xsi:type='annotation'>" +
    "<notetext>" + notetext + "</notetext>" +
    "<subject>" + subject + "</subject>" +
    "<objectid>" + objectId + "</objectid>" +
    "<objecttypecode>" + objectTypeCode + "</objectyypecode>" +
    "</entity>" +
    "</Create>" +
    "</soap:Body>" +
    "</soap:Envelope>";

    // Prepare the xmlHttpObject and send the request.
    var xHReq = new ActiveXObject("Msxml2.XMLHTTP");
    xHReq.Open("POST", "/mscrmservices/2007/CrmService.asmx", false);
    xHReq.setRequestHeader("SOAPAction", "http://ift.tt/R2TpER");
    xHReq.setRequestHeader("Content-Type", "text/xml; charset=utf-8");
    xHReq.setRequestHeader("Content-Length", xml.length);
    xHReq.send(xml);

    // Capture the result
    var resultXml = xHReq.responseXML;

    // Check for errors.
    var errorCount = resultXml.selectNodes('//error').length;
    if (errorCount != 0) {
        var msg = resultXml.selectSingleNode('//description').nodeTypedValue;
        alert(msg);
    }