Hi,
So you're going to do the following:
1. Set up a B2D folder, and make that the target for your backups. Schedule it at the required time and let it run.
2. Once done with #1, look under Backup Tasks in Job Setup, and choose New Job to Duplicate Backup Sets. Select the option to Duplicate backup sets following a job. Once done, you can give it a name, and then select the tape drive under Destination --> Device and Media.
What will happen is the primary job will kick off first, and back up to disk. Once done, the secondary job will kick off and backup to tape. Don't forget that you can set notification for this too so that you know what's going on.
Laters!