After stumbling upon your version 0.2, I found out that I already was using version 0.1 of your script. Works as (almost) as intended. :-)
Edit: I must withdraw a star (point). I found that when you remove the focus from the password input (by clicking onto the name again, for example) the password field becomes invisible.
You can easily fix this by remove the 'onblur'-attribute to the password input. No big problem as the problem does not occur when you let firefox fill in the password anyway.