Under which circumstances can Finnair luggage fees be paid with Finnair Plus Miles (for TATL)?
a) Does the ticket need to be issued by AY?
b) Does the flight need to be booked on an AY flight number?
c) Does the flight need to be operated by AY (and not BA or AA, for example)?

What about a TATL on AY metal with a subsequent domestic flight on AA (C2 to C1)? Could luggage still be paid with Finnair Plus Miles?
Any experience with such combinations?