Thank you for your replies. No, I don't have any special status.

I think I ended up at the US callcenter of miles&more. I had contacted the service in Poland first (since I wanted to fly LOT) but they very totally unhelpful and told me I had to call where I live.

I will visit the two websites you pointed out to check for availability. Thank you!

I can not book any awards ex YHZ or ex BTS it seems. And, yes, it would be faster via LHR, but I prefer LOT as the fees&taxes are much lower with LOT. No fuel surchage with LOT. And I'm not in a hurry. :-)

Plus, since Austria is introducing a tax on plane tickets, I'd rather fly back from BTS. Nice small airport with a new terminal there which I haven't used since Sky Europe went down.

For the taxes&fees of any other award ticket I can buy (almost or sometimes even more than) a normal ticket.