I knew this is what you were driving at and this is the mistake you make, assuming there were kickbacks involved.
The US has a process known as Foreign Military Sales program. A foreign country, Kenya in this case, makes a request to the US DOD on what they want. The US DoD will then ask manufacturers to submit bids for tender, or they can single source if the requested material is only built by a single manufacturer.
The US DoD will then pay for the request and Kenya will re-imburse the US DoD.
This is the same issue that affected the AT-802L Longsword aircraft sale to Kenya because some Congressman wanted the deal to go to another company in his district which builds similar aircraft (Iomax Archangel), but not what Kenya had requested. He thought there was corruption involved but there was none.
Here is the report by Government Accountability Office
