International connection 2 different airlines at PEK

I'm flying in from Hong Kong to PEK on China Air. Then connecting from there to Tokyo on Japan Air (JAL). What is the best way to get a ticket printed for JAL at PEK if I can't figure out a way to do so before leaving out of HKG? I went through the international transfer check before and I recall they needed to see a boarding pass before passing through. Also even if you do make it through the terminal, there was no airline help desks found inside and it doesn't seem like the departure gates are well staffed either.