Preheat grill to low heat. Place bread loaf in the center of a large sheet of foil (big enough to wrap entirely around the bread later). Slice bread into 1 1/2 inch thick slices but do not cut through the very bottom of the loaf, leave about 1/4 inch at the bottom intact so that all of the slices still stay connected.
Spread butter between each slice and use your fingers to rub some over the top of the loaf. Sprinkle garlic powder between each slice trying to cover as much surface area as possible. Sprinkle minced garlic on top of the loaf and finish off with the Italian seasoning.
Wrap the bread loosely in the foil (make sure it's sealed shut but has some room for the heat to circulate). Place foil-wrapped-bread on the grill and cook for 15-20 minutes turning over half way through.
Carefully unwrap the foil, pull bread slices apart and serve warm.
Servings will vary depending on how many slices you get out of the bread. A long slender loaf will yield more slices than a short wide loaf.