I've done a ton of business in Africa and have three comments.

1. It's not just the President who wears a suit. Most business leaders, vice president level on up, wear suits. So when I'm meeting at that level I'm expected to wear a suit and tie. If it's a banker you are meeting, even lower level people wear suits. Ditto for certain government ministries.

2. In all tropical locations the locals often wear long sleeve shirts. It is due to formality and it's ok for them because they are accustomed to the heat. I found that I get accustomed pretty quickly and as long as I have general access to air conditioning that a long sleeve shirt is fine. So khaki slacks and a long sleeve shirt is what I generally wear unless I'm meeting someone senior or going to a special dinner.

3. Shoes are a concern. If you are going to be walking around a lot, you will ruin a nice pair of Gucci's. So I only wear those if I'm riding in a Mercedes to the bosses office. Otherwise black shoes with thick rubber soles is the way to go.