My v2.4 implementation is a type of SBC suitable for the edge of a customer network. I have topology_hiding working for INVITEs. I have mid_registrar working for REGISTERs. I do not have them working together. I'd like to completely hide the topology of the inside network when sending traffic to the outside main registrar / ITSP. topology_hiding does a nice job with that for INVITEs, but mid_registrar still leaks details through Via headers and such. Is it possible to combine them?