How to? - KDEWallet and Firefox - more than one uname/pwd for a site

In SeaMonkey and Firefox on Windows I had the convenience of saving more than one username/password for a site and when I visited that site again I would get a popup with the list of usernames from which I could select the one I want. I thought only KDEWallet didn't have this but now I see that even Firefox on Linux doesn't have it. So can anyone tell me how to get this functionality? Shriramana.