I have been able to map drives using Hamachi, but it requires manually setting up the network settings on each spoke connection. If you go into the Network and Sharing center, and go into the properties of the Hamachi Network adapter, then change the IPv4 settings. Add the IP address of your "Hub" server's Hamachi address as the primary DNS server. Then you should be able to use mapped drives across the Hamachi tunnel.
What I haven't figured out, is how I can make this change globally through the Hamachi settings.