Step 1: Ensure you have prerequisites set up for your web server and hosts, as per this forum post (Once off process)
Step 2: Add new Password Record configured as follows:
Screen 1: Ensure you configure the below 5 options correctly and enter in the password for the account. If you configure an Expiry Date it will automatically change the password when that date is reached.
Screen 2: Ensure you select the correct Privileged Account and the Reset Juniper ScreenOS Password reset script. Also confirm the Password Reset Schedule is enabled if you want the password to automatically change when the Expiry Date occurs
Screen 3: Confirm the Validate Password for Juniper ScreenOS Account validation script is selected