In order to specify my custom url to point to my internal HTTP I need to add this configuration manually in the install config in the YAML view:
platform:
vsphere:
clusterOSImage: http://mirror.example.com/images/rhcos-43.81.201912131630.0-vmware.x86_64.ova?sha256=ffebbd68e8a1f2a245ca19522c16c86f67f9ac8e4e0c1f0a812b068b16f7265d
CU request is to have an option to specify the url to my internal http server that contains the ova, in the cluster creation proccess in the UI (same as the imageContentSourcePolicy for example).