Rest DSL IN/OUT types

[Alan Camillo]

Hello!

I've had some problems trying the new rest dsl from camel and I'd like to
know if there is a way to do this:

restConfiguration()
    .component("netty-http")
    .host("0.0.0.0")
    .bindingMode(*RestBindingMode.auto*)
    .port("{{server.port}}");

rest("/mail")
    .post("/send")
        .consumes("text/xml")
        .produces("text/xml")
        .type(A.class)
        .to("direct:msg");

Until here I received a A.class from the clients with no problem.
But from "direct:msg" I'd like to return a (xml) String to the client. Like
this:

from("direct:msg").routeId("direct:msg")
    .log("message received: ${body}")
    .setBody(new ConstantExpression("<?xml version=\"1.0\"
encoding=\"UTF-8\"?><ok>ok</ok>"));

And than, error:
java.io.IOException: javax.xml.bind.MarshalException
 - with linked exception:
[com.sun.istack.SAXException2: unable to marshal type "java.lang.String" as
an element because it is missing an @XmlRootElement annotation]

Look obvious, but I'd like to know if there a way to do this.
Thanks!
Alan Camillo