yen1 welcome to FT!
Don't be surprised if a moderator moves this to TravelBuzz - you may get better answers in TravelBuzz anyway.
If China Southern fly there, you may be able to book using KLM/NW, as China Southern is a partner airline of KLM. Other than them, I've never seen a Chinese airline allow web bookings, and my travel agent has in the past had problems booking on some of the regional carriers.
Good luck!