How to use the RPCManager.setLoginRequiredMarker("...")

I use SmartGWT 4.1 and SiteMinder for SSO

For Session Timeout and Relogin case, I found the function RPCManager.setLoginRequiredMarker("...") and there is html file loginRequiredMarker.html in SmartGWT download zip.

My question is, if I don't want to change my existing login page can I set the content in loginRequiredMarker.html as String into RPCManager.setLoginRequiredMarker("...")?

If I have some marker for the http response when session timeout case, (mainly from SiteMinder agent...), I should customize the javascript inside loginRequiredMarker.html for our case?

Is there any sample of how to use RPCManager.setLoginRequiredMarker("...")?

thx in advanced