Preheat oven to 350 degrees; line a shallow baking pan with foil.
In a small bowl, whisk together hoisin sauce, catsup, soy sauce, garlic and sugar.
Place tenderloin in baking pan and coat with hoisin sauce mixture.
Roast in the middle of the oven 35 to 40 minutes, or until a meat thermometer inserted in center registers 160 degrees.
Cool pork completely in baking pan.
In a small bowl, stir together sauce ingredients until sugar is dissolved.
Transfer pork to cutting board and cut meat across the grain into thin slices.