Pour the beef stock into a stock pot or large deep skillet over medium-high heat. Stir in the toenjang until dissolved. Add the kelp and garlic, and bring to a boil. Put in the tofu, cabbage, daikon and yellow squash, cover and return to a boil. Cook gently for 5 minutes. Then add the green onions and hot pepper, and boil for a minute, or until the onion and pepper become fragrant and brightly colored. Limit the cooking time to no more than 15 minutes. Remove and discard kelp. Serve immediately.