Backup tape rotations

Our legal department would like us to implement a one year rotation of our e-mail backup. We’re using Veritas BackupExec with NT4 in 15 tape DLT library. Where do I go for a better understanding of what’s involved with providing this solution? Possibly due to our configuration I have many questions and would like to begin an exchange where I could pose questions and possibly get solutions.

Thanks,
MJ