Hi,
Currently "StorageTek SL500 Library" not supported device by Backup exec.
You may also refer to the following link to check the Hardware compatibility chart for Backup exec
http://support.veritas.com/dsl/lists/device_ddProduct_BEWNT_media_all_prod1_NT9.htm
For Backup exec v10.0
http://support.veritas.com/docs/274347