What could be the reason behind the game's failure to treat the Hamachi network as a LAN?

Question

I'm having an issue with Hamachi LogmeIn and Red Alert 3. I looked for answers and tried many workarounds but to no avail.

I am trying to set up a virtual LAN so that I can play Red Alert 3 with my friends, each one in a different state or country. But I cannot see any of them in the LAN lobby in Red Alert 3! But if one of them comes over and we connect to a physical Lan via router, we can see each other and play.

Using Hamachi LogmeIn, I can flawlessly use services and apps like Remote Desktop, IpMessage, and access all Shared folders regardless of where my friends are. But Red Alert 3 will not work over Hamachi LogmeIn, even when I choose Hamachi's IP from the game's options.

I tried many things: disabling firewalls, raising Hamachi's adapter priority, disabling the antivirus, disabling IPv6, running Hamachi and the game as admin, etc.

Still, on a physical Router disconnected from the internet, all services including the Red Alert 3's LAN feature work perfectly. But on the Hamachi's VPN, all other services work except for the game's LAN feature.

The only thing I have not tried is port forwarding, since I have no control over the internet-connected router, neither can I ask the admin to do that. The internet is provided by the university (Entreprise wifi). My understanding, and I could be mistaken, is that I don't even need port forwarding if I'm tunneling via a VPN.

One of the PC's is Windows 8.1. The other is Windows 7. Both games are genuine with unique serials. And I'm using Hamachi's latest version.

Thanks for your help and suggestions.