New
#1
This link has more details (steps to do it are for version 16.04 - 18.04 is slightly easier)
Here is how to do it for 18.04. Works on SCU
A guide how to run Ubuntu 18.04 in Enhanced Mode in Hyper-V - Windows 10 Forums
NOTE: 18.04 is not yet officially issued for a couple of week or so. Above guide uses the daily prerelease builds.