I have an ASA 5525-x Pair that do Failover with each other and connect to a Juniper SSG-5 pair. There is a VIP on both ends. We now have a secondary ISP (CenturyLink - CL) connected to the ASA pair and if the primary link (Verizon - VZ) fails, we want the tunnel to be rebuilt across the secondary ISP link to the SSG-5 Vip.
That basically will use the outside-VZ interface to reach the remote Juniper peer, as long as the ICMP traffic can reach Google DNS out of the interface outside-VZ. When the IP SLA fails, the second route through CL, which has a higher administrative distance, will kick in, so the ASA will use it to reach to the Juniper.