I think he's talking about the multicast helper which is in the Wireless (and CAPSMAN) system which does multicast to unicast conversion at the radio interface. It's needed to make things like mDNS and DHCP more reliable and also allow for use of VLANs with wireless clients. I am surprised it doesn't exist in WifiWave2.
Search for it in
https://help.mikrotik.com/docs/display/ ... +Interface
So yeah, FTOMs what's the go with multicast to unicast conversion in WifiWave2? Does it exist in some other form?