Cisco VPN client acting up in Hyper-V virtual machine

When I work remote against my customers I have one virtual machine per customer. This has many advantages for me. One advantage is that I do not have to install all the different VPN clients and stuff. Another advantage is that I isolate my connection to the customer from the virtual machine and not bridging connections between different customers. Lately I have had several customers that use Cisco VPN client for remote connections. It works great, except for when you use it within a Hyper-V virtual machine. If I try to connect the Cisco VPN client from within the virtual machine, I get this error message:

“VPN establishment capability from a remote desktop is disabled. A VPN connection will not be established.”

The workaround is very simple. If you run the virtual machine in Window mode and not full screen you will see this little icon:

This icon is for switching between enhanced session and basic session.

If you switch to basic session and run the VPN connection again it will succeed. After the VPN is established you can switch back to enhanced session.