Legal and ethical issues on overseas job recruitment in nigeria

We are a young recruitment firm based out of Lagos Nigeria and we have a few requirements from overseas market.
Could anyone guide us to know if any guidelines need to be followed before we can recruit candidates for the overseas market. For example, do we need any other Nigerian Government licensing other than the business registration with CAC or any other formalities.
We will appreciate professional advice from our fellow consultants especially on the ideal percent charged for the recruitment services rendered to such overseas market.
Pls help!!
Yilbel