That question has already been answered - because people always open new threads, we have to answer everything multiple times.
http://www.pprune.org/african-aviati...10-11-a-6.html
If you have studied Air Law for your ATP you should know that you can only validate that what is in you original license and only as long as that license is current and for a maximum of one year - so no SEP IS a problem.
A lot of you guys going down to Africa will not get in - so it is only worth going if you can afford to speculate and treat the whole thing like a vacation scenario if the job search turns out negative. That is also why a lot of people drop the idea and never actually ever turn up anyway. The aviation community down there is tiny.