Flagrum, that did it!
I opened dcs, unchecked trackir aiming, closed dcs, opened a mission, closed it, reapplied the setting, closed dcs, and then reran it. Now it works. However, I now have the same problem as the guy from the other thread, in which I cannot switch to the gunner position.
On closer inspection, it seems that the huey on the training mission, has no gunner. Maybe this is an older mission, and an update screwed that up? I'll report back later on that front. In any case, thanks a lot. I was getting frustrated!