Client EJB Interceptor context data serialized into privateData map on server side

On the client side we have an ejb interceptor which puts some custom data to the ContextData map with context.getContextData().put(...). This data is then serialized to the invocation stream (via writeAttachements). But on the server side this data is deserialized to the 'priveData' member of the enclosing InterceptorContext instance of the current InvocationContext object (with readAttachments). This data map is not accessable from our server side standard ejb interceptor with context.getContextData().get(...)