On a 20x18-inch sheet of heavy foil place the potatoes, carrots and onion. Drizzle with olive oil and sprinkle with Italian seasoning, salt and 1/4 teaspoon black pepper. Bring up long sides of foil and fold to seal. Roll up short sides of foil to enclose. If necessary, manipulate foil packet to fit in cooker, making sure the brisket is completely covered with the foil packet.