Place the Fib lines on your chart where you need them. Next, right click you mouse to bring up the options menue. Select the object list. Next when you see Fibo in the object list, double click on it to edit the Fibo parameters. Select the tab that is "Fibo levels". Next press the Add button. In the Level box put in .786 and in the Description place 78.6 and that should do it.
That new fib level should be there for you from now on when you fire off the indicator.