How to implement method with System.Xml.XmlNode parameter?

How do I format the System.Xml.XmlNode parameter? The node I need to pass in looks similar to the following:

<FilterItems>
    <FilterItem FilterItemId="55555">04/16/2015</FilterItem>
</FilterItems>        


System.Xml.XmlNodeServiceReference1.ClientServiceSoap.GetReportResults
    (string username, string password, int reportId, System.Xml.XmlNode templateValues)
    {
        username = "myUserName";
        password = "myPassword";
        reportId = 930;
        templateValues = ???

        throw new NotImplementedException();
    }