Finnair Plus - Redemption ex-TLL?

I'm having some difficulty working out how to use redemption points ex-TLL. Trying to use the Finnair website to search for options just keeps failing for pretty much anything other than HEL, giving an "Error message (1000003) not found for Language Code 'GB'" result, which is pretty far from useful (and even switching language to Finnish, with the idea that I could run the error through Google Translate didn't help —.it still gave me the same error message in English!)

Do I really need to book a separate TLL-HEL return (at an extra 24,000 points) just to make any other redemption?

If I were you I'd call AY..their booking engine is bad even for normal paid tickets when the ITN is more complicated than a simple return ticket (not showing all available flights etc..)