1. For marinade, in a bowl combine soy sauce, orange juice, orange zest, brown sugar, ginger, garlic, rice wine vinegar, vegetable oil, chilli sauce, and sesame oil. Mix.
2. In an airtight container, pour ¾ of the marinade, reserving ¼ for grilling.
3. Drop beef pieces in it. Mix, and place it in refrigerator for at least 8 hours or overnight.
4. In the last four hours of marinating, add mushrooms in the container with beef.
5. Preheat grill to high (350-400 degrees F).
6. In skewer, thread green bell pepper, beef, broccoli, mushroom, and onion. Repeat until all the pieces are skewered.
7. With a brush, apply reserved marinade on skewers.
8. Place skewers on preheated grill, and cook for about 12 minutes or until meat is slightly pink in the center, turning frequently and basting it with reserved marinade.