Just got them on the phone again.
They seem interested in cash upgrades only, not with miles.....
Upgrade with miles will only be possible at the airport, not at the online check-in (not be possible due to the leg in train....).
And at the railway station, they won't be able to do the upgrade, so I'll have to wait to be at CDG, so the chance of availability will be very limited.
So how to use my miles then ?
Reply : award ticket, exit seat, or meal !
Great......
