Creating a SOAP webservice without a namespace for the parameter

Question

First here is what I want to do: I want to create a webservice that calls a java function void doSomething(ParamType value); when it receives the SOAP message

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
    <soapenv:Header/>
    <soapenv:Body>
        <paramType>
            <elem>test</elem>
        </paramType>
    </soapenv:Body>
</soapenv:Envelope>

Note the missing namespace of paramType.

I created the following class to contain the doSomething function:

@WebService(name = "doSomethingPort", targetNamespace = "http://www.tim.org/nsClass/")
@SOAPBinding(parameterStyle = SOAPBinding.ParameterStyle.BARE)
public class DoSomethingImpl {

    @WebMethod(action = "http://sap.com/xi/WebService/soap1.1")
    @Oneway
    public void doSomething(
            @WebParam(name = "paramType", targetNamespace = "http://www.tim.org/nsParam/", partName = "value") 
            ParamType value) 
    {
        System.out.println("Hallo Welt");
    }
}

and the following class to hold the parameter:

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "", namespace="http://www.tim.org/nsXMLType/")
@XmlRootElement(name="paramType", namespace="http://www.tim.org/nsXMLRootElem/")
public class ParamType {

    @XmlElement(required = true)
    protected String elem;

    public String getElem() {
        return elem;
    }

    public void setElem(String value) {
        this.elem = value;
    }
}

The webservice is started with:

Endpoint.publish( "http://localhost:8090/services", new DoSomethingImpl());

The result after some testing is: This webservice accepts messages in which the paramType has a namespace: <nsp:paramType xmlns:nsp="http://www.tim.org/nsParam/">

When I leave the targetNamepace declaration on the parameter he uses the targetNamespace on the DoSomethingImpl class (the http://www.tim.org/nsClass/)

Removing the namespace there causes the webservice to create a namespace from his package name.

Does anybody has an Idea how I get a webservice accepting that message? I would prefer to repair/reconfigure my existing webservice, but I would accept other ways to accept the message and call the doSomething function.