As other posters have noted: You do not need to book this as two separate awards
if you are doing North America --> Europe --> SAfrica. If you do NAm --> Singapore --> South Africa (also an optional routing) you will need to do two awards with *A.
Note, however, that with Oneworld, the Pacific routing has the same cost as the Atlantic routing. If you have the time, you might find ORD-HKG-JNB an interesting option - especially with a stopover in HKG. Mind you, it's much further... but expedience may not be the requirement.
I would not wait for SAA to enter * b/c their entry may occur at any time - including after 09/05. Book the tickets on UA/LH (or wherever) and if SAA joins in time, consider the $150 to change.
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