First, configure your amahi install in the usual way at the [http://www.amahi.org/user control panel]. You must use the IP address of the VirtualBox "Host only" interface as your gateway (in my case, 192.168.56.1). You can also set the dhcp to a single start/end address(i.e. 192.168.56.10). This will ensure your VM has only one possible IP and that will be the one you add to the profile.