But, it seems that i can't render them with motion blur.
According to VRay's manual regarding Alembic support through VRay Proxy, there should be a separate file along with the Alembic mesh that describes the velocitiy of the mesh:
Most likely this problem is on VRay's end, but getting a separate velocity file per alembic mesh from RealFlow wouldn't hurt either, would it?"V-Ray will recognize velocity information for motion blur if it stored either as standard Alembic velocity, or as a 3d vector array property called arbGeom.v or arbGeom.velocities."
Any thoughts or insights about this?