Every multinational company that wants to do business in Southern Sudan has its counsel nagging it about US government sanctions. If you listen to the explanations/intent and deconstruction of the sanctions policy and implementation, it is a lawyer's fantasy; full of caveats, conditions, clearance processes, but thin on the reality of this regions' common standards and practices for business.
Here's a link to a US government page that has updated definitions of the bilateral sanctions regime (that means only the US government applies them to Sudan and for the most part only US citizens/businesses are obliged to observe them). One thing is for certain, read carefully the first sentence:
Are you a U.S. individual, firm, or business entity seeking to do business in Sudan?
If you answer yes, then keep reading. If not, get back to work!