Here are a few things that I've learned in setting up Hamachi Gateways...
It's easier to install the client on the gateway before creating a Hamachi Network. This makes it available to select during the "Create Network" wizards.
At least for gateways, it is easier to create the network from the LogMeIn.com site, not the Hamachi client.
The Hamachi Client not only runs on all client computers, it also runs on the Gateway computer.
Running the gateway on VMWare vSphere ESX 4.0 (also ESX 3.x) requires the network adapter in ESX to be configured in "Promiscuous Mode". If it is not configured, network connectivity on the server VM will be lost when the Hamachi Client on the Gateway is installed.
Based on the above, I suspect "Promiscuous Mode" would need to be turned on when using a more advanced SOHO or business grade switch like an HP ProCurve. Consumer grade switches already have it turned on.
Must "Disable UAC" on Vista and Server 2008. Google to find out how. On 2008 this can be done by Start -> Run -> msconfig -> Tools tab -> "Disable UAC"
I've gotten Hamachi to works on Server 2003, Server 2008, and XP as gateways.
I've been able to get Hamachi to work as a client on Windows 7 Ultimate, Vista, and XP.
On Windows 7 Hamachi required my RSA key to be authenticated. This showed up as a blocked connection. Right click -> Details... -> then double click Authentication and click "Trusted"
If the client running on the gateway is "Powered Off" it disconnects all Hamachi connections essentially turning the entire Hamachi Gateway network off.
Tunnel notes - Under connection "details... " in the Hamachi client
"Direct" links are the best tunnels and I typically see Round-trip times of 45-60ms where I'm at.
"via Relays" is the next best tunnel and I typically see 100-200ms Round-trip times.
"via Servers" is the slowest and with the free Hamachi product I've seen 500+ms Round-trip times.
When Hamachi first connects it finds the fastest link then if the fast link drops off for whatever reason, it reconnects with the next fastest tunnel until it connects "via Servers"