Hi Janne,
Backup Exec 10d and 11d you are required to install a remote agent on the server holding the share...period...and must have the license on for an remote agent on you media server. Typically once you get the remote agent installed you want to backup the share at the folder/drive level and not the share itself. The share permissions and stored in System State/Shadow Copy backup of that server in the registry.
Hope this helps
---cheers
shirmal