I'm going to Ozzy with a stopover in NRT (AY + QF) and coming back via SIN (BA + AY) but as you said HKG and BKK are also options - in fact BKK priced out lowest (by not much) when I booked my ticket. The key, I think is that AY have flights to/from these Asian destination and codeshares with QF/BA onwards, so they might have options via KIX/NGO/PEK/PVG as well. That said my NRT-SYD flight is with QF code.
Worth noting that starting/terminating your trip NOT in Finland will drop your price by €€€€ - so our lovely lady from Brisbane should save a bucketload going to BER with just a stopover in Finland and buying a separate ticket HEL-RVN-HEL. But she was given htis advice already many times to no avail.
