Are you using flat hierarchy i.e. all meshes are siblings under the root node ?
Seems to be that way, yeah. I think most b3d exporters do this, don't they?
If so it might be possible that their origins are all at Zero even though the vertices are in the right place.
This what I was thinking. The origins are all in the right place within 3dsMax so it's happening somewhere along the export pipeline from 3dsMax to UU, from UU to Gile[s] and from Gile[s] to B3d. Probably somewhere involving UU.
Unfortunately, I have to live with it if I want users to be able to use their own meshes.