Hi,
If you have procured this BCWF for a new box, it is very likely that you have a BCIS subscription instead of legacy BCWF username/password. If this is the case, your device serial number will be already tagged/entitled at our subscription server to download BlueCoat webfilter DB. All you have to do is to set the Data Source: as Intelligence Services as in the below screenshot
If you are indeed having a username/password, you can add it in the above page by setting the Data Source: as WebFilter. This username/password will remain same through your renewals. In case of customer losing the password, contact Symantec Customer Care or TAC to get the information retrieved for you.