All perfect praise be to Allah The Lord of the Worlds and may His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
If by Foreign Exchange Trading, you are referring to (Forex|) or (Margin Trading), then they aren`t permissible because they include violations of Sharia. We have already clarified these in Fatwas (697) and (645). In addition, a Muslim isn`t allowed to help promote and market that which is unlawful. Therefore, we recommend that you look for a new job.
As for the salaries that you have received, it is permissible that you benefit from them, because what is unlawful relates to the work that you have been doing, and not the money itself. And Allah knows best.