This question is related to a previous thread of mine but that one's rather long so I will summarize it here and ask a quick question.

The user of my application doesn't seem to understand how browsers work. He wants to log in to our application using the admin login, and log in to our application in a second IE tab using the billing login, and perhaps log in to our application in a third IE tab using the customer service login. Each of these users is served different renditions of the same page. He doesn't understand that because the application uses session cookies, the most recent login is what he will be logged in as in all three tabs.

Does anyone know of a link that explains this well? He's technical and has a programming background but none of it is .net or even ASP. And he asked me to do this:
Please document why you can not work on this problem – so that it may be logged.
even though it was all explained to him before (he tried to report it as a bug again today...short memory!)

Thanks!