Hi,
You could create a second duplicate job for the Backup to Disk backup, this time with the second tape.
If the above doesnt answer your question, could you please elaborate on the following:
1)What kind of autoloader are you using?
2)How many slots?
3)How many drives?
NOTE : If we do not receive your reply within two business days, this post would be marked assumed answered and would be moved to answered questions pool.