I have never come across ExtremeZ-IP, so don't know how it works.
It looks like it runs as a service, so you may be able to install the service on each node in the cluster, then use the Wizard provided with SFWHA to cluster the service, and any shared storage. Then you'd need to see how to replicate any settings you might need. If these are stored in registry you need to hunt down the relevent section and use Registry Replication.