How's the VirtualBox networking setup? I would suggest to setup something like this:
1st NIC for NAT, where you pull emerge-webrsync files from
2nd NIC host-only via vboxnet0, then setup an static IP (ie 192.168.56.2/24) to SSH on.
On VBox, the first and only NIC, by default is setup to NAT. You CANNOT ssh into that. It's ip will be something like 10.0.2.x/24. No way you can ssh into that.
Lastly, dont' forget to check that the virtual cables are plugged in. Give it an extra kick just to make sure