jetty - Jetty does not want to listen on port 80

Question

I want to change the default port the Jetty 9 is listening on from 8080 to 80. I've edited the jetty-http.xml file to look like this:

<Call name="addConnector">
<Arg>
  <New class="org.eclipse.jetty.server.ServerConnector">
    <Arg name="server"><Ref refid="Server" /></Arg>
    <Arg name="factories">
      <Array type="org.eclipse.jetty.server.ConnectionFactory">
        <Item>
          <New class="org.eclipse.jetty.server.HttpConnectionFactory">
            <Arg name="config"><Ref refid="httpConfig" /></Arg>
          </New>
        </Item>
      </Array>
    </Arg>
    <Set name="host"><Property name="jetty.host" /></Set>
    <Set name="port"><Property name="jetty.port" default="80" /></Set>
    <Set name="idleTimeout"><Property name="http.timeout" default="30000"/></Set>
  </New>
</Arg>

However, for some strange reason when I startup the server it still listens on 8080.