Why is Apache CXF not respecting 'nil="true"'

I am using Apache CXF 3.0.2 for a client and a server. On the server there is a fairly simple web service that accepts various parameters, one of which is a String array:

<xs:complexType name="getThing">
  <xs:sequence>
    <xs:element minOccurs="0" name="connection" type="tns:connectionID"/>
    <xs:element maxOccurs="unbounded" minOccurs="0" name="types" type="xs:string"/>
  </xs:sequence>
</xs:complexType>

When the client calls this, it might be that it wishes to pass a single null value for "types" and that's where I encounter problems. The SOAP message from the client looks like this:

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <ns2:getThing xmlns:ns2="http://serverl.url/">
      <connection>Connection details....</connection>
      <types xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:nil="true"/>
    </ns2:getThing>
  </soap:Body>
</soap:Envelope>

I think that's correct, but CXF on the server translates that into an array with a single empty string value; not an array containing a null value. This then causes various issues with the server code.

The interface the server implements looks like this?

ThingResult getThing(@WebParam(name = "connection") ConnectionID connection, @WebParam(name = "types") String[] types)
{ code }

And if 'nil="true"' isn't valid, then why is CXF generating it?

A null array works OK (the client omits the element from the message and the server interprets that as a null) but not an array containing a null value. Why is CXF behaving this way and how do I configure it so the server deserialises the SOAP message correctly back to what the client sent?

I have searched everywhere for the answer and am fairly sure I am missing something embarrassingly obvious!

edit: Added code sample

I could find no way of making CXF behave (either in WSDL generation or client respect of the generated WSDL).

Instead I had to modify the server code to treat nulls and empty Strings as if they were equivalent.

An bit of a hack that shouldn't be needed, but seems to work.