tradehill有个API是撤回BTC用的:
https://api.tradehill.com/APIv1/USD/SubmitWithdrawalRequest参数说明如下：
name: TradeHill Username
pass: TradeHill Password
method: The method of withdrawal. Refer to the Method column here.
amount: The amount to withdraw.
box_a: Additional transaction details possibly required for this request.
box_b: Additional transaction details possibly required for this request.
box_c: Additional transaction details possibly required for this request.
box_d: Additional transaction details possibly required for this request.
box_e: Additional transaction details possibly required for this request.
box_f: Additional transaction details possibly required for this request.
box_g: Additional transaction details possibly required for this request.
我不了解的是，method参数需要填写什么内容。如果我要撤回Bitcoin，那么这时method需要填写什么呢？
