Wirelessly posted (BlackBerry: BlackBerry8530/5.0.0.601 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/417)
"HKG-JNB (Cathay Pacific)
JNB-CPT (British Airways)
CPT-JNB (British Airways)"
If the Explorer award itinerary is going to end in JNB, then you will not be able to pass through JNB earlier in the itinerary. (No connections or stopovers are permitted at the first or last city on an Explorer award.)
Try pricing the trip home on South African from CPT, rather than JNB.