problem with ajax and session expiration

[Rogerio Baldini das Neves <ro...@powerlogic.com.br>]

Hi Guys,

When I do a submit in an Ajax Button and user session is expired, screen
freezes.
Security is handled by Tomcat container through security-constraint in
web.xml and this is my logon.jsp snnipet:

		<form method="post"
action="<%=response.encodeURL("j_security_check")%>">
			User:	<input name="j_username" type="text">
			Password:	<input type="password"
name="j_password">
			<input name="btnLogin" type="submit" value='OK'>
		</form>

I can execute an Ajax submit to discover if session is expired or not. And
if it is expired I redirect to logon page. 
But in this case I will duplicate all my posts and it's not a good solution
to a very accessed application.
And if I try to logon in another page, I get a ViewExpiredException.

Doens't  Trinidad do it by itself ? Why not ? 
Is there some plan to do it ?

Is there a smart way to solve this problem ?

Thanks a lot
Rogerio.