Clustering iWorkflow

I assume there must be a reason you don't want to sync iWorkflow using the mgmt interface but this is I believe the recommended configuration. If you want to manage the data traffic on another network that should work, meaning discovering and pushing services to BIG-IP devices but use the mgmt network to support the iWorkflow communications. So, check the "use management network for HA peer communications" and I suspect this will resolve your cluster creation issue.