You can also do by "setup" command , While setting up the initial configuration it will ask for partner vif name for failover purpose ( refer below )
should interface vif01(primary virtual interface name) takeover a partner IP address during failover ? : yes
Please enter the partner virtual interface name to be taken over by vif01 (primary virtual interface name) : (give the partner virtual interface name)
you need to change this values in both the controllers
There will be separate IP for second controller , you need to log in through that IP