You could try EU-Africa-EU/Asia-SWP-Asia/NA-EU, with / indicating non-stopover routings. The only thing is that you can only do the EU/Asia transit if you fly out of Accra / Lagos, so you would be limited where you could go there, otherwise you may have to utilise the JNB-HKG flight to get out of Africa. In general, maximising miles works better through S. America than Africa, since Lan Chile provides you with better route choices than are available intra-Africa.

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