What you would look into doing is a duplicate job. What this does is basically copy your backup set to another medium (tape to disk; disk to tape; disk to disk; tape to tape etc).
Set up your job to backup your resources. Once done, go into
Job Setup --> New Duplicate Backup job Set,
and choose the option to
Duplicate existing backup sets.
From here you can select what you'd like duplicated, and when to run it via a schedule. Your destination device will be your removable drive, but don'[t forget to set it up as such in Backup Exec.
This should be what you are looking at doing. Do a test, and let us know how it goes.