Single Sign On Solution (WebSeal) interfering with Adobe Spry

We have an application which relies heavily on Adobe Spry. For authentication purposes a Single Sign On Solution is used. (Its a WebSeal, but I don't think that matters to much)

We now have pretty much exactly the problem described here: http://www.ibm.com/developerworks/tivoli/library/t-ajaxtam/index.html#user_session_expire i.e. we get a timeout of the WebSeal session during a AJAX request.

The net effect currently is that a logon screen is de开发者_如何学Csplayed somewhere inside the page, where the result of the AJAX request should get rendered.

Question: Is there a way to setup some kind of exception handling for Spry along these lines? If you don't get a valid dataset, but a webpage (or redirect to a webpage) please display it in the toplevel frame of the application.