How to create a Hyper-V Internal network

I have a Windows 2008 server running multiple Hyper-V guests. I want to create a Hyper-V "Internal" network. So far, I cannot get anything to communicate.

1. I created the Internal network adapter in the Hyper-V manager
2. I assigned each VM's network adapter to the internal network adapter
3. I assigned an IP address to the host (10.1.0.1) with no default gateway (since it also has an external network card with a gateway)
4. I assigned each guest VM an IP (10.1.0.x) with 10.1.0.1 (host) as the gateway
5. I installed the Routing and Remote Access roll on the host

The problem is that neither the host or the guests and ping any other IP on the network. I have no communication at all between any of the guests. The guests in question are Windows 2008 R2 Enterprise, standard install (not Core).

What am I missing to get the host/vms to communicate via the internal network adapter?

If the VMs can't ping even between themselves, then something is definitely broken here, and it's not related to the RRAS service running on the host; regardless of their default gateway's behaviour, machines placed on the same network and with proper IP configuration should be able to talk at least between themselves.

Did you try disabling Windows Firewall on the guests?

Also, as per Greg Askew's suggestion, I'd try removing RRAS on the host; maybe it's messing up something with Hyper-V networking.