My bank has three fields, not two. Instead of username / password, it has access number / user id / password. If I fill those fields in and accept the prompt to have Firefox remember passwords, the access number is correct, but the password gets remembered in the user id field, so each time I log in, I had to clear the user ID field and then re-enter both it and password. So, I entered the password as user ID and accepted the change, so now I can just type in the password... but Firefox prompts me to remember a new password. I'd like a way to tell it to never offer to change passwords on that particular page again, since the change it will do will never be correct.

Yes, I know, "This is a problem with your banks web site, your bank sucks, you should burn their building down to teach them a lesson and go bank with someone else". Still...