add namespace defintion in XML converter

XML converter renders objects with "simple" xml, ie
<book id="1"><title>Life</title></book>

In order to integrate with some other tools (Apache ODE), it is necessary to add a namespace to identify data type definition. The output should be like

<book xmlns="http://www.example.org/myapp" id="1"><title>Life</title></book>

the namespace could be defined at application level (Config.groovy) or domain class level (as an attribbute ?)

Thanks you