Recipe courtesy of O'Neill Williams.
In a large resealabe bag, combine the lemon juice, rosemary, oil, salt and pepper; add fish. Seal bag and turn to coat. Refrigerate for 1 hour.
Drain and discard marinade.
Set EGG for direct cooking (no convEGGtor) at 350°F/177°C. Grill fish on Perforated Cooking Grid until fish flakes easily.
In a small saucepan, combine the remaining ingredients. Cook over medium heat. Serve with fish.