Get message "One or more devices are unreachable" after configuring a High Availability pair

Using Big-IP Lab virtual edition version 11.5.1 Build 0.0.110

Although specifying a High Availability configuration via the Setup utility completes without errors, when navigating to Device Management -> Overview and clicking one of the devices, the following message appears:

One or more devices are unreachable. Resolve any communication problems before attempting to sync.

I suspect the problem was leaving all the OVF template Source Networks (Management, Internal, External, HA) all mapped to a single "Destination Network" when deploying the VMware template (at this stage only one network had been configured on the ESXi server), rather than trying to effectively perform this remapping with the VMware Edit settings dialogue and F5 Setup Utility after the deployment had completed and a second VMware network had been configured.

I realise I may need to reinstall the OVF templates from scratch (and request reactivation of the two licenses), but could someone kindly confirm the above explanation is a possible cause of the problem first?

The steps I actually followed were to remap Network Adapter 2 to VM Network 2 in the VMware Edit Settings dialogue for each F5 host, then run the Setup utility with the following setup options...

Internal Network Configuration

    High Availability/Failover Method:  Network

    Self IP                 
         Address        11.1.0.100
          Netmask   255.255.255.0
          Port Lockdown Allow Default

    Floating IP
    Address     11.1.0.50
            Port Lockdown   Allow Default

Internal VLAN configuration

    VLAN Name   internal
    VLAN Tag ID auto
    VLAN Interfaces

            [moved Available item 1.1 to Tagged]
            (Can see from Network -> Interfaces: Interface List that 1.1 has automatically received the MAC address for the 2nd ESXi network)

External VLAN configuration

    Select existing VLAN
    Select VLAN     internal (ie reuse all attributes entered on Internal VLAN page)

High Availability VLAN configuration

    Select existing VLAN
    Select VLAN     internal (ie reuse all attributes entered on Internal VLAN page)

Config Sync Configuration

    [Accept default of:]

    Local Address       11.1.0.102

Failover Unicast Configuration

    [Accept defaults of:]

    Local Address       Port    VLAN
    11.1.0.102      1026    internal
    137.72.93.53        1026    Management Address

Use Failover Multicast Address

[Leave unchecked]

Mirroring Configuration

    Primary Local Mirror Address    None

At this point I was unable to ping either host from the other.

I've successfully tested the 2nd VMware network by configuring it as a network between two RHEL6 hosts.

Thanks!