Not trying to downplay your award selection, but isn't a trip between Milan and Bangkok one of the cheapest possible long hauls available on Finnair? That's a route I would normally pay for J on and get full 200%+ miles, and use award miles on more expensive routes instead. Anyway, did you only check for business class availability? If you have vouchers available, you could try booking an award flight in economy and upgrade it with vouchers. And if you have the flexibility, you could also look at using award miles to/from Helsinki, and buy a separate ticket to Milan and back, the availability will probably be better.