Information about Hamachi(or other VPN) users

Hamachi doesn't support connecting from iOS devices at this point, so you'll have to host the Mine Control server on your normal network (and using port forwarding) if you want people from the internet to connect to it from their iOS devices (iPhone, iPad, iPod Touch). You can still run the Minecraft server in this tool through Hamachi just fine.
From the looks of it, people have been asking for an iPhone client since 2009, so it's hard to say if they'll release one or not.

This also applies to other VPN clients as well. Unless you can connect to that VPN service from the iOS device, you will run into the same issue.