Hi,
To be honest I have to do these so rarely that I wouldnt remember the exact procedure either and would have to check online.
Actually the last time I have had to reconnect to a firewall for which I didnt know the passwords for was a PIX 501 but its been like 4 years or something. At that time atleast Cisco provided a .bin file that you could load to the PIX through rommon I think and it would erase the current passwords to default and let you connect to the device.
I am not sure but I think I remember someone just asking for those .bin files for the same purpose but I am not sure if Cisco has them online anymore (I havent looked)
I also cant remember did the Cisco firewalls provide a way to boot the firewall without the start configuration with changing the configuration register like it was with the Cisco routers.
Have you tried to connect to the PIX through console?
- Jouni