Yeah, it has rather a delicate flavour that can be easily overwhelmed by other ingredients. To be honest, it tends to work better as the main attraction - it holds is shape rather well when cooked so you could try braising it, either in stock or maybe from a japanese angle with mirin, soy, and sesame? I've never tried it this way but i'd imagine it would work rather well. By all means try it in your soup though! I think, flavour-wise, it would compliment carrot and/or squash perfectly well, and would add a subtle 'mystery flavour' to the soup. And if you're feeling particularly adventurous, it would be wonderful as part of a fresh miso soup.
I have also used it as the basis of a coleslaw, which can be mayonnaise-based for with grilled meats, or marinated in citrus and oil for an accompaniment to fish. It's very good.
Just play around...that's when all the best dishes are created! :oD