So it's been a while since I last attempted to import a 3d character. With version 4.x I just gave up: nothing worked.
Today I felt like trying it again in the latest version. Downloaded a Mixamo character with some animation, imported in Blender, exported again as Collada, and imported into Visionaire.
...and what do you know: it imported and played the animation, but the bones deformed the character. Now, that I can deal with. The textures were all there, and the static character looked good. And the animation did play (although the character looks like a maldeformed monster :-)
Will experiment some more, and then create a small tutorial how to set up an animated 3d character in Blender and import into Visionaire. If I can fix the bone deformation issue, that is! But this is quite exciting.