Originally Posted by wonderman

I'm looking into this also. I've done B2B at CGK, the method is to ask politely the flight attendant mid flight to contact ground staff prior to landing and inform them you have a booking for the return flight and you want to get back on the plane.
Someone will then meet you on the ground, put you through a side door straight into the departure gate and go and print your paper boarding pass.

I've done this twice.