I managed to get this working using connections in the /etc/snapmirror.conf
Add something like this to the snapmirror.conf on the destination filer...
SOURCEHOST = failover(SOURCEHOST-mirror-ifgrp1, DESTHOST-mirror-ifgrp1) (SOURCEHOST-mgmt-ifgrp1, DESTHOST-mgmt-ifgrp1)
SOURCEHOST:VOL DESTHOST:VOL - 15 0,6,12,18 * *