译成英文"我们以前做了很多的美国订单,但是都是通过中间商做的,这次与美国直接做是第一次."

We received many orders from America(the states) before, but not directly (did bussiness) with them.
And this is the (very) first time that we have bussiness with America.
我搞外贸的，这样写应该没有什么问题。

希望大家在诚信的基础上,合作成功!
I do hope we can have good cooperation based on muturally trust.

We did a lot of American orders before, but all is passed in the center the company to do of, do with the United States directly this time BE a first time.
Hope everyone on the foundation of the trustworthiness, cooperate the success!