Backup a folder from a network share/mapped drive using urBackup?

Hi I have a folder on a network share which is mapped to a Windows client that gets backed up with Urbackup. I want UrBackup to also backup this folder on it’s mapped drive (letter Z). I added the path of the mapped drive to the clients backup paths and enabled file backups but it failed saying access denied (how do i give it the mapped drive password?). I also tried giving it the UNC path but then it fails when trying to index/snapshot. Is this a supported feature? Hope you can help.