can you try something like this?
[root@ve1023:Active] config b virtual address list all
virtual address 172.28.19.79 {
enable
limit 0
arp enable
route advertisement disable
mask 255.255.255.255
floating disable
unit 0
server any
partition Common
}
[root@ve1023:Active] config b virtual address 172.28.19.79 floating enable unit 1
[root@ve1023:Active] config b virtual address list all
virtual address 172.28.19.79 {
enable
limit 0
arp enable
route advertisement disable
mask 255.255.255.255
floating enable
unit 1
server any
partition Common
}