JAX-RS client proxy objects ignore @Encoded annotation

The JAX-RS client ignores @Encoded annotations on client methods. I am trying to implement an API which takes a "key path" that looks like a UNIX directory e.g. to set key "/foo/bar/baz" you would POST to http://myservice:80/key/foo/bar/baz

I was hoping that

@Path("/key/{keypath}")
@POST
Response setKey(@Encoded @PathParam("keypath") String key);

would work, but the ProcessorFactory checks for @Encoded and then ignores it:

ProcessorFactory.java:78

      boolean isEncoded = FindAnnotation.findAnnotation(annotations,
              Encoded.class) != null;