@pe1chl: No, dstnat happens in prerouting, so traffic coming to router (no matter if it will end up in forward or input) can be matched by dstnat rule. Traffic from router doesn’t come through prerouting in RouterOS.
@msatter: External device would work fine, but sometimes it may not be desired or even possible to add it.
@TomjNorthIdaho: Nope, to quote WinBox: “Error in - non zero ip address or non zero ipv6 address expected!”
But something can be done. I posted possible solution in the other thread, because it belongs there more. But I don’t like it.