I think the problem is not the mesh orientation but the child initial orientation.
If you want to rotate a child over his own axis (global), put a ,1 parameter at the end of the rotate command.
RotateEntity child,rx,ry,rz,1
If you want to rotate a child over his own axis (global), put a ,1 parameter at the end of the rotate command.
RotateEntity child,rx,ry,rz,1