I'm looking at possibly flying CPT - MUB (Maun, Botswana). The flight is operated by South African Airlink. I'm wondering if this flight (or any SA airlink operated flight) is bookable using Star Alliance partner miles (i.e. UA or Singapore), or even other partners like Virgin Atlantic miles? I did an award search on united.com, and it returned nothing even with flexible dates.

Any information or assistance would be appreciated.