In a VCD VPG, when choosing IP Mode of "none", it is not possible to specify any network settings. This is expected behavior.
Currently, when failing over into VCD using Guest Customization, it is not easy to change the virtual network of a VM but keep the same static IP. In order to do so, the IP Mode on the "NICs" tab within the Edit VPG wizard must be set to "Static Manual," and the current IP manually populated. This is in addition to setting the virtual network on the "Recovery" tab.
It was perceived that this should be possible by only setting the virtual network on the "Recovery" tab, but setting the IP mode on the "NICs" tab to "None". However, when doing this, the virtual network only gets applied to the vApp that is created, but cannot be applied to the VMs by Guest Customization.