Kindly cross check Backup Exec v10.0 compatibility list and make sure if the device that you have mentioned (StorageTek library SL500) is listed.
Stand Alone Drive Hardware Compatibility List (HCL) for VERITAS Backup Exec 10.0 for Windows Servers
http://seer.support.veritas.com/docs/274347.htm
http://support.veritas.com/docs/274348
We would like mention you that if the device is not listed in the HCL, then its explicitly not tested with Backup Exec and we do not guarantee 100% functionality (proper operation) with Backup Exec software.
However, you may try and use OEM drivers and check for proper operation of device and its working with Backup Exec software.
Title:- How to use original equipment manufacturer drivers with VERITAS Backup Exec (tm) for Windows Servers 9.x
http://seer.support.veritas.com/docs/253974.htm
We hope this helps.