Cook the pasta in plenty of rapidly simmering water until al dente. Drain and rinse under cool water, then drain well again. Meanwhile, steam the broccoli and carrots together in a large saucepan with a small amount of water until both are just tender-crisp. Drain and rinse under cool water, then drain well again. Combine the pasta with the broccoli-carrot mixture and all the remaining ingredients in a large serving bowl, and toss well. Cover and refrigerate until needed, or serve at once.