On VM creation trough the UI console, its impossible to add an additional interface and select a network that was create by OVN-Kuberentes's using UserDefinedNetwork or ClusterUserDefinedNetwork CRDs.

4.19.0-0.nightly-2025-05-04-082442

100%

1. create OVN bridge-mapping "localnet1"
$ oc apply -f - <<EOF
apiVersion: nmstate.io/v1
kind: NodeNetworkConfigurationPolicy
metadata:
  name: br-ex-localnet1
spec:
  nodeSelector:
    node-role.kubernetes.io/worker: ''
  desiredState:
    ovn:
      bridge-mappings:
        localnet: localnet1
        bridge: br-ex
        state: present
EOF

2. create new project
$ oc new-project reproducer

3. create localnet topology using CUDN CR, selecting the project namespace name

4. $ oc apply -f - <<EOF
apiVersion: k8s.ovn.org/v1
kind: ClusterUserDefinedNetwork
metadata:
  name: localnet1
spec:
  namespaceSelector:
    matchExpressions:
     - key: kubernetes.io/metadata.name
       operator: In
       values: ["reproducer"]
  network:
    topology: Localnet
    localnet:
      role: Secondary
      physicalNetworkName: localnet1       
      ipam: {mode: Disabled}
EOF

5. Create new VM using the wizard, and select the network created in (4)  
  VirtualMachine > create > from template > pick any..
  Customize VirtualMachine > Network Interfaces > Add network interface
 
 **The network created in (4) does not present.** 

Its impossible to select OVN-K user defined network on the "Add network interface" modal.

Allow connecting VM to OVN-K user-defined network.