I'll assume you have configured the options correctly on the Exchange page in the backup job. There is a lot of documentation available describing how-to's and best practices for backing up Exchange. One of those is to configure your Exchange backups as a separate job - do not backup other files, folders, servers, etc., along with the Information Store on your Exchange server(s).
The Information Store only holds your Exchange Storage Groups; if you expand it in the selection list, you will see the Storage Groups listed. The Information Store does not contain your Exchange configuration files, SystemState, or any other files on that server. It is important to back those up separately, especially the SystemState, otherwise it will be impossible to recover your Exchange configuration from a server crash. Also, if Exchange is part of an Active Directory domain, make sure the SystemState of all your DCs is backed up regularly. Much of the Exchange configuration is housed there.
To verify whether Exchange is truly being backed up, attempt a test restore. Go to one of your StorageGroups in the restore selection list, and you should be able to choose individual mailboxes and even messages. If not, either your BE patch level is behind, or you are not properly configuring your backup jobs for Exchange.
It is also important to backup certain folders on your Exchange CAS, Hub, and Edge servers. Most of the files and folders that must be backed up are clearly listed in the course work for Microsoft course # 5050A, but there are also guidelines in the Backup Exec 11d Admin Guide, and I'm sure you can find it on-line or in the Exchange documentation, as well.
Hope this helps