Hi: I have heard of a few diet restrictions in certain indian regions, including no foods like onions/garlic since they come from inside the ground. I looked up the Iskon standards. Bummer that it excludes mushrooms, because mushroom soup would be a great idea. Can you have potatos? I don't see them included or excluded. I was also going to suggest miso soup without the bonito (fish flakes), but it appears soy beans are prohibited. It also appears lentils are prohibited? Oh boy, that's tough because lentil soup can be delicious.
If potatoes can be included, consider potato soup. Also, how about various squash soups, such as zucchini? My central-euro culture has a wonderful squash/zuccini soup that's made with a little fresh dill. These are the soft squashes, similar to bitter melon, but, not so bitter. You can explore other squash varieties, too, they may be called "gourd" in some areas (think pumpkin, butternut squash, etc).
What about carrots, or celery?
Other soups to consider: green bean, split pea soup, watercress, cabbage, cauliflower. You can do these like plain soup, like a stew, or even "cream of..". You might also consider multiple vegetable in one soup; for example, green bean with caulflower, or tomato with watercress. Or put them all together and make a chili 
As far as raw-tasting, are you allowed to broil the veggies first? Maybe do that with the asparagus, broil it to pre-cook, instead of sauteeing. Then put that into water and continue your regular cooking, blending to make it a cream of roasted asparagus soup :)!
