Amazon May Have Trouble Dodging California's New Online Sales Tax

Under the law Amazon has a CA presence because it has wholly owned subsidiaries like a9.com and Alexia in CA. I know that the corporate veil is not impervious, but can CA pierce it in this instance, or can only the Feds do it? Has it been tested in the courts? I dont have a clue, but would be interested in hearing from someone who does.