In a food processor, mix together the peppers through red pepper flakes until relatively smooth; will stil be a bit chunky. Transfer to a bowl and mix in the capers. Keep refrigerated and bring to room temperature before serving.
Combine rosemary, oil, garlic and pepper in a food processor until thick and almost smooth. In a shallow pan, spread the mixture over the roast and refrigerate for at least two hours before grilling.
With a charcoal grill, prepare briquettes and grill for slow roasting. We have made this with the charcoal grill and added hickory wood chips for extra flavor. With a gas grill, set the temperature to medium or medium-low. Place the roast on top rack and slow cook the roast with the cover on, turning the roast every 10 or 15 minutes. Grill for approximately one hour or until the roast registers at 140 degrees. Transfer pork to platter and tent with foil, and let stand for about 15 minutes. Serve with the red pepper sauce alongside.