the changed flavor is almost definitely because of the low sodium. i would use the v8 for soup and be sure to add salt to taste. if you want to keep it simple, just chop up some carrots, celery, and onion, and dump them into the v8 with a can of beans (something white, like cannelinni or navy). add some basil, oregano, and let it cook for a bit.
that's why i love soup; eaaaasy