Arquillian test POST to Servlet

I have the following test that works for testing a GET method on a servlet:

    @ArquillianResource
    URL deploymentUrl;

    @Test
    @RunAsClient
    public void testLoginServlet() throws IOException {
        URL url = new URL(deploymentUrl, "login");
        StringBuilder builder = new StringBuilder();
        BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream()));
        String line;

        while ((line = reader.readLine()) != null) {
            builder.append(line);
        }
        reader.close();

        assertNotNull(builder.toString());
    }

What's the best way to test a POST call to the same servlet, passing 1 parameter?

Should I be creating a WebTarget and using that or is there a trick with Arquillian that makes it easier. I thought there were annotations but can't find anything.