That box only does purging from the demo database according to the manual. =)
You will want to take a look at this section instead :
To configure data retention settings for the Veritas Backup Reporter Management Server
- Connect to the Veritas Backup Reporter Management Server with administrator-level privileges.
- For instructions on how to start the console and connect to the Veritas Backup Reporter Management Server, see the Veritas Backup Reporter User’s Guide.
- In the console navigation bar, click Settings > Global Settings.
- In the console’s Administration page, click Data Retention.
- In the Data Retention dialog box, edit the value in the Backup Log Data field and any other fields you want to modify.
- Click Save