I have a similar situation. Booked on SYD - HND - HEL - BER (the last two segments being operated by Finnair) and I'd love to be able to short check my bags to HEL and not board the final leg to BER (the scheduled stopover in HEL is 2:35). As far as I can tell, my bags will go through to BER by default (even though HEL is the first stop in the Schengen area) unless I can convince a check-in agent in SYD to short check. How likely is it that I'd be able to do that?