For the Filling, place meat in large saucepan. Sprinkle with 1 teaspoon of the garlic powder and pepper. Add water to cover meat. (Add additional water if necessary to completely cover meat.) Bring to boil. Reduce heat to low; simmer 20 minutes or until meat is cooked through. Remove meat to cutting board. Reserve cooking broth in saucepan. Cool meat slightly then cut into small cubes. Set aside.
Place pepitas, chilies, sesame seed, onion powder, salt, remaining 1 teaspoon garlic powder, cinnamon stick, annatto and cloves in blender container; cover. Blend on high speed until finely ground. Add tomatoes, green pepper and 1/2 cup of the reserved meat cooking broth. Cover. Blend until smooth, stopping to stir ingredients once or twice to make it easier to blend.
Pour mixture into medium saucepan. Add 1 cup broth and lard. Bring to boil. Reduce heat to medium; simmer 15 to 20 minutes until slightly thickened. Stir in meat, olives and capers. Set aside.
For the Tamales, place 9 cups broth and enough reserved meat cooking broth to equal 13 cups in 8 to 12-quart deep stockpot. Bring to boil. Add masa and salt, stirring constantly until well blended. Reduce heat to low; stir in lard until shiny and smooth. Remove from heat. Set aside to cool.
Meanwhile, fill another large pot with water. Bring to boil. Wash banana leaves then cut into 28 (10-inch) squares. Reserve extra pieces. Boil cut squares and extra pieces for 10 minutes. Remove from pan. Drain and cool.
To assemble each tamale, arrange a banana leaf square on work surface so that veins of leaf are vertical. This makes it easier to fold the leaf without breaking it. Spread 1/2 cup of masa into a 4-inch circle in center of leaf. Make a small well down center of the masa. Spoon about 2 tablespoons filling mixture into the well. Fold both sides of banana leaf over filling. Fold over top and bottom of leaf. Tie tamale with string or thin banana leaf strip.
To cook the tamales, place steamer basket on bottom of large pot. Add 4 cups water. Line basket with some of the extra banana leaf pieces. Place tamales in steamer basket. Make sure tamales are not touching the water. Cover tamales with remaining banana leaves. Bring water to boil. Cover. Steam on medium heat 1 1/2 hours or until banana leaf peels away easily from tamale and masa is slightly firm. (Tamales will continue to firm up when removed from heat.) Add additional boiling water to pot as necessary.