Just figured out, that Group Pivot point doesn't actually make difference in direction of the model in Outerra.
You have to rotate all (group) in the world axis, so it points forward along world Y axis.
However this doesn't work on bone objects. They've been rotating opposite way (probably as their Pivots were rotated 180 on Z axis).
Fixing the pivot points of bones, made another problem, they not appearing in Importer at all.
So will try to figure it out later.