In my VCO plugin how do I store xml in the plugin config file instead of key/value pairs?

Hi ,

     I'm following the solar-system vco plugin sample to store confg info on the server side plugin config file, what the sample plugin does is to store key/vaue pairs:

        Properties prop = new Properties();
        prop.setProperty("solar.system.home.planet", homePlanet);
        prop.setProperty("solar.system.isPlutoClassifiedAsAPlanet", plutoClassifiedAsAPlanet);
        if (stream == null) {
            SDKHelper.savePropertiesForPluginName(prop, pluginName);
        }

    But I saw in other plugins like vCenter server plugin, the config info is stored in xml nodes which is far more flexible tha key/value pairs, I wonder what API I should use to do this? Thanks!