@OrionNZ Thanks a million for your help!
Knowing that the events themselves were OK let me narrow down my search. It turned out that, for some mysterious reason, the first two lines of the events.txt file weren’t being loaded by my Mobiflight instance — and that’s exactly where I’d put the two definitions, of course.
After inserting two dummy lines at the front everything works perfectly now and I can fully enjoy this wonderful plane. Thanks again!