I'm not sure how much ATLAS is controlling the API here, but to add an extra argument in the RaiseClientCallbackEvent making the Client variables accessible in the callbackevent would be very useful. I'ts solvable already today by returning a joined value and split it up within the client return function, however it would be easier for non javahackers to fully rely on the Get and Set variable functions.
Something like....

RaiseClientCallbackEvent(ByVal eventArgument as String, ByVal autoSpace as ClientAPIAutoClass) as string impl....
          autoSpace.Get(VarNamne)
          autoSpace.Set(VarName) = Value

ok, just a 2 cent's
/Rob