I finally decided to have ParameterizedWiseTreeElement extends WiseTreeElement since the T of JAXBElement could be mapped on any kind of WiseTreeElement.
All WCF tests generating JAXBElements run fine now.
Apart from the error in [1830147], Parameterized element are not correctly displayed in the web interface.
Moreover we should evaluate whether it's fine to have them descend directly from SimpleWiseTreeElement; perhaps it might be better to have ParameterizedWiseTreeElement be something similar to the Complex and Group at the same time (i.e. JAXBElement could be modeled as a Wise...
