Just after the release of version 0.9.10b7, the Dev Team has made public an update. The new version, 0.9.10b8 supports the activation keys from SAM unlock. So now if you have this unlock, you can just go to options in this version of Redsn0w and backup the keys and save yourself the time and effort of going manually for the backup.
So if you want to create the back up, just go to extras, select Even More and Back up. Your otherwise long process should be shortened dramatically! Resulting in backup of activation codes from /var/root/Library/Lockdown.