You can have F5 health monitor in two ways: 1) Check if the server is up. This can be done by pinging the IP with ICMP packets. 2) Service check monitors. This are used to to check the health of the services(example HTTP, DNS, POP, SIP, stunnel, etc) hosted on the servers.
Why don't you try option 1 above? Not ideal but could be a workable solution.