PIServer Volumio2 image

PIServer on a x86 device (Debian Stretch) can be used as a boot server for Raspberry PI 3 devices. Using the PIServer you don’t need SD cards anymore, just boot your RPi 3 over the network.

I’m playing with my PIServer today and found only standard Debian (Lite) images to boot from.
Does anyone know how to create a boot-image for Volumio 2??
Or is it just a matter of copy an existing SD-content to the tftpserver directory with the proper MAC address?

Any help would be appreciated!