Response Document in wps java code

Question

I'm implementing some java process into Geoserver OGC-WPS standard. I start with the following simplest code:

package org.geoserver.wps.nais;

import org.geoserver.wps.gs.GeoServerProcess;
import org.geotools.process.factory.DescribeParameter; 
import org.geotools.process.factory.DescribeProcess; 
import org.geotools.process.factory.DescribeResult; 

@DescribeProcess(title = "helloWPS", description = "Hello WPS Sample")

public class HelloWPS implements GeoServerProcess {
    @DescribeResult(name = "result", description = "output result")
    public String execute( @DescribeParameter(name = "Hello!!", description = "Hello, ... ", )  final String nome )
    {
        return nome;
    }
}

It returns a String. I need to receive a xml response document.

Anyone know how to modify the code?