Tomcat – How to Disallow HTTP Methods Case Sensitively

I have put the following in the web.xml of my application to attempt to disallow PUT, DELETE, etc.:

 <security-constraint>
 <web-resource-collection>
  <web-resource-name>restricted methods</web-resource-name>
  <url-pattern>/*</url-pattern>
  <http-method>DELETE</http-method>
  <http-method>PUT</http-method>
  <http-method>SEARCH</http-method>
  <http-method>COPY</http-method>
  <http-method>MOVE</http-method>
  <http-method>PROPFIND</http-method>
  <http-method>PROPPATCH</http-method>
  <http-method>MKCOL</http-method>
  <http-method>LOCK</http-method>
  <http-method>UNLOCK</http-method>
  <http-method>delete</http-method>
  <http-method>put</http-method>
  <http-method>search</http-method>
  <http-method>copy</http-method>
  <http-method>move</http-method>
  <http-method>propfind</http-method>
  <http-method>proppatch</http-method>
  <http-method>mkcol</http-method>
  <http-method>lock</http-method>
  <http-method>unlock</http-method>
 </web-resource-collection>
 <auth-constraint />
 </security-constraint>

Ok, so now:

If I do a request with method of DELETE I get a 403 back.

If I do a request with method of delete I get a 403 back.

BUT

If I do a request with method of DeLeTe I get OK!

How can I make it disallow these case-insensitive?

Edit: I'm testing it with a C# program:

    private void button1_Click(object sender, EventArgs e)
    {
        textBox1.Text = "making request";
        System.Threading.Thread.Sleep(400);
        WebRequest req = WebRequest.Create("http://serverurl/Application/cache_test.jsp");
        req.Method = txtMethod.Text;
        try
        {
            HttpWebResponse resp = (HttpWebResponse)req.GetResponse();

            textBox1.Text = "Status: " + resp.StatusCode;

            if (resp.StatusCode == System.Net.HttpStatusCode.OK)
            {
                WebHeaderCollection header = resp.Headers;
                using (System.IO.StreamReader reader = new System.IO.StreamReader(resp.GetResponseStream(), ASCIIEncoding.ASCII))
                {
                    //string responseText = reader.ReadToEnd();
                    textBox1.Text += "\r\n" + reader.ReadToEnd();
                }
            }
        }
        catch (Exception ex)
        {
            textBox1.Text = ex.Message;
        }
    }

txtMethod.Text is a text box where I'm typing the method name. When there is a 403 an exception is thrown which is caught in the catch block.

The cache_test.jsp contains:

<%
response.setHeader("Cache-Control", "no-store, no-cache, must-revalidate, post-check=0, pre-check=0");
response.setHeader("Pragma","no-cache");

out.print("Method used was: "+request.getMethod());
%>