Finally, I found one solution - not too elegant, but at least, it works:
1. Export the character and animation as collada.
2. Create ani file from the collada model with the Uhro3D AssetImporter
3. Put the collada model to the scene
4. Remove the animationconroller
5. In your code load the animation, and create animationstate
6. In the Update event call the addtime function on the animationstate.
Probably, it is not the ideal solution, but I didn't found any better.