How am I supposed to use Apache XML-RPC's TypeConvertorFactory on the server side?

I am struggling to get Apache XML-RPC to call my TypeConvertorFactory at all. It is calling it on the client side (only return values confirmed to work so far, haven't tested parameters) but the server side isn't calling it at all.

My initialisation code looks like this:

XmlRpcServlet servlet = new XmlRpcServlet();
XmlRpcServerConfigImpl config = new XmlRpcServerConfigImpl();
config.setEnabledForExtensions(true);
servlet.getXmlRpcServletServer().setConfig(config);
servlet.getXmlRpcServletServer().setTypeConverterFactory(
    new ServerTypeConvertorFactory());

The API looks like this:

private interface API {
    AvailableLicencesResponse availableLicences();
}

AvailableLicencesResponse is just an ordinary boring, albeit deeply nested JavaBean.

At the moment, the server sends this response as Base64 (this works because I called setEnabledForExtensions(true) - but if I don't call that, I get "unexpected end of stream" type errors instead, with no addition开发者_JAVA技巧al error anywhere to tell me why.)

I have set breakpoints inside ServerTypeConvertorFactory and it seems that none of the methods are being called on the server. The same breakpoints show the client calling convert() when the server hands back the result, but the result is already the correct type due to serialisation magic so I don't need to convert it.

Essentially, what I am trying to do is to implement a wire protocol which conforms to standard XML-RPC (and doesn't use huge amounts of Base64 data...) while still having an API which doesn't require a thousand casts and calls to Map.get(). I also want to avoid having to make more calls than necessary, which is why I'm returning a bean instead of having separate methods to get each property of it, which would have worked too.

(Also, if there is a simpler to use API than this one, I'm open for suggestions. It started out being really easy, but that's until you need to customise it. Also, anyone suggesting Axis or other SOAP-based APIs will be shot at dawn.)