Hello:
Just to give you an idea, I booked this in May (paid and ticketed by email with Mindpearl in CPT):
CPT-JNB-SYD-DRW-BNE-AKL-MEL-HKG-SIN-NRT-PEK-HKG-JFK-SFO-DFW-LHR-HEL-MAD-CAI-LHR-CPT
Base price: ZAR66070
Taxes:ZAR 7112 (about 11%)
Total: ZAR 73182

Sort of similar to yours, but:
1) 20 segments (only available before Jun 1st)
2) I have North America, not South America
3) I have two departures from LHR

However, I was told that for AA to ticket, either trans-Atlantic or trans-Pacific had to be on AA. I believe that you can't do this without including North America.
I was also told that you cannot book any AA codeshares unless you are connecting directly (no stopover) to/from an AA trans-oceanic flight.

Good luck!