Model exporter xml - how customize response content-type

Hi community,

i developed a custom XML exporter:

"

/**
 * XML export used to generate XML render on servlets.
 */
@Component(service = ModelExporter.class)
public class CustomXmlExporter implements ModelExporter {
    private static final Logger LOG = LoggerFactory.getLogger(CustomXmlExporter.class);
    @Override
    public boolean isSupported(Class<?> aClass) {
        return true;
    }

    @Override
    public <T> T export(Object model, Class<T> aClass, Map<String, String> options) throws ExportException {
        StringWriter stringWriter = new StringWriter();
        try {
            JAXBContext jaxbContext = JAXBContext.newInstance(model.getClass());
            Marshaller marshaller = jaxbContext.createMarshaller();
            marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
            marshaller.marshal(model, stringWriter);
        } catch (JAXBException e) {
            LOG.error("\n Marshell Error : {} ",e);
        }
        return (T) stringWriter.toString();
    }

    @Override
    public String getName() {
        return "custom-exporter";
    }
}

"

and it work fine! 

now, during the integration test, i catched the necessary to customize the response content-type from:application/xml;charset=iso-8859-1 to:application/xml; charset=utf-8.

How can i reach the goal? i don't understand where set the content-type override.

Here my model:

@Exporters({
        @Exporter(name = ExporterConstants.SLING_MODEL_EXPORTER_NAME, selector = "list", extensions = ExporterConstants.SLING_MODEL_EXTENSION, options = {
                @ExporterOption(name = "MapperFeature.SORT_PROPERTIES_ALPHABETICALLY", value = "true"),
                @ExporterOption(name = "SerializationFeature.WRITE_DATES_AS_TIMESTAMPS", value = "false")
        }),
        @Exporter(name = "custom-exporter", extensions = "xml", selector = "list")
})