Wal-Mart has long battled to keep unions out of its stores in the US. Now, the world's largest retailer has picked the same fight in China. The All-China Federation of Trade Unions, which oversees all workers' organisations in the country, says its efforts to establish unions in Wal-Mart outlets have been repeatedly rebuffed. The federation says all companies, foreign and local, are required to establish a union, using funds from a 2 per cent levy on wages. "Many times we have tried to talk to Wal-Mart about this, but they knock us back with excuses, like the boss is not...