How to call server asynchronously?

Dear Community,

I have tried to setup asynchronus custom business service calls from Open UI. But even though it's supposed to run asynchronously, UI is blocked until response is received. I would expect, that user is able to navigate through Siebel and make changes, while waiting for the response.

I have followed steps from bookshelf:

- Bookshelf v8.1/8.2: Allowing Users to Interact with Clients During Business Service Calls

- Bookshelf v8.1/8.2: Application Model Class

This is code for client side:

function ServerCall(){

  var bsSvc = SiebelApp.S_App.GetService("My Service");

  var psIn = SiebelApp.S_App.NewPropertySet();

  var psOut;

  psIn.SetProperty("message","PING..");