How to give VM internet access while keeping my Host reachable via RDP?

Question

I have a Window DataCenter 2008 running on a remote machine (at OVH) with the hyper V role, and I want to run several VM on this server.

I have already installed a VM with Windows 7 but I can't give it Internet access.

I followed this guide Windows 8 Hyper-V - how to give VM internet access?

So I have a problem: When I configure my external virtual switch and create it, I lose the connection to my host and I am unable to access it again via RDP.

My host IP is set in static but still can't ping it after the creation of the vSwitch.