In order to automatically mount CIFS (Common Internet File System) folder for backup on your PBXware, you have to edit /etc/fstab.
SSH into your PBXware and edit fstab:
Add line to the bottom of the fstab file and make sure that noserverino: option is present.:
//REMOTE-SERVER/SHARED-FOLDER /mnt/DESTINATION-PATH/ cifs username=USERNAME,password=PASSWORD,**noserverino** 0 0
Make sure to replace values with correct username, password, appropriate paths to folders on the remote system, as well as your desired mounting location on PBXware.