82579V - Hyper-v - External Network issue

Hi,

I use Windows 8 PRO 64bit and installed the HYPER-V and created an external LAN allowing the host to share NIC . As soon as created the external LAN, i lost the internet connection on HOST, but the virtual Machine is able to connect to internet. If i disable he virtual network and then re-enable it, from network properties, the connection works both on host and on virtual.
But if i reboot the host, i'm in the same situation as before, and have to disable and then enable again the virtual network.

Any clue ? It seems i'm not the only one having the issue, but can't find a permanent solution.

http://blog.siliconvalve.com/2012/09/26/fix-windows-8-and-hyper-v-virtual-switch-problems/

Many thanks in advance

Fabrizio