I am afraid that if the active page view should be changed on toolbar button click, you need to add as updated control the RadMultiPage as well.
I suggest that you try replacing the RadAjax with ASP:UpdatePanel and see if it makes any difference. In order to isolate the problem further, you can try removing the UpdatePanels on the main page and leave the RadAjax settings only.
Check it out and let me know how it goes.
the Telerik team