Add an own external service

I was wondering if it is possible to add an external service to Apache Knox. I have followed the Apache Knox’s user guide and it seems that you can add a service to the topology section of the cluster.xml file. I’ve tried adding the following lines to that configuration file:

<service>
<roles>MYSERVICE</roles>
<url>http://some-external-url:some-port/service-context</url&gt;
</service>

Any clue about how to add an external (or internal for that matter) services besides Hadoop’s to Apache Knox?

Regards,
Iván.