To generate a test certificate, do the following:
Exit from Netscape Navigator if it is running.
Make a backup copy of the key3.db and cert7.db files, which are located in your Netscape user's directory (the Program Files\Netscape\Users\<username> directory in Windows and the ~/.netscape directory in UNIX).
Set up a password for the key and certificate databases, if you have not already done so. When you run signtool, you will be prompted to enter this password. To set up a password, choose the Communicator/Tools/Security Info menu item, and click the Passwords link on the left. Follow the directions in this dialog box to set your password.
Run the signtool command with the -G <name of certificate> and -d <location ...