Trading the Chinese RMB

As mentioned in the Wall St. Journal, the Chinese currency Yuan, or RMB is tradeable externally for the first time.

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Daily trading in the yuan has grown from zero to $400 million in the past few months... Global trading in yuan allows businesses to buy and sell the currency to finance trade, investment and borrowing...

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(Predictable) manipulation?

Now that RMB/USD and RMB/EUR FX contracts are available at CME, and that there's all this talk of Chinese government's influence over the currency, the next logical question becomes a matter of exploiting it for a profit. OK, so the US claims that the RMB is kept artificially low within a predictable range. If that is true, then this trade could result in practically risk free profits.

So what's the deal here? If everyone believes they know how the RMB's being manipulated, where's the volume over CME? Something's gotta give.