Hello,
It's possible to do this directly in the CUBAC administration web page.
Enter in the menu User Configuration>Queue Management.
Here you'll find a part "Overflow".
Enter the Hunt Pilot number in the "Overflow Number" parameter.
Check the "No operator overflow" box.
If there is no operator online (Application no started or PC down), the calls will be send to the Overflow Number. It works with a Phone number, so it should also be OK with a Hunt Pilot.
CHeers
jp