Reimporting doesn't work in my case. As a workaround we already defined the network name in the provisioning settings manually, but it is still a strange issue. feature or bug what's the difference ;)
At a customer we just upgraded all the HyperV servers to HyperV 2012R2. Now we got an issue that the 'Virtual Network Name' is saying '  Is this a known issue?
vWorkspace 8.0 | HyperV 2012 R2 | Virtual Network Name 