Unless Italy has different Lithium battery restrictions than the rest of the world, VML and one or two spare batteries can be carried as carry on luggage on international flights, but not as checked baggage.
As for International shipping as by UPS or Fedex, there is a $62.50 hazardous good surcharge for a shipment of multiple Lithium batteries. Customer service can give you the exact number the $62.50 covers -
info@paulcbuff.com.
There is no ITA or TSA requirement for batteries to be discharged or disconnected during shipment to my knowledge. Again, Customer Service can point you to all regulations.
In fact, discharging batteries completely is not a good idea as long term storage of fully discharged Lithium batteries can shorten battery life or even cause failure.
As for VLX batteries, We have recently discovered that ITA regulations limit transport of Lithium batteries on passenger flights to 160 watt hours. We have just complete re certification of existing 169 Wh VLX batteries downward to 158.75 Wh to meet these requirements.
We are preparing to send existing VLX customers replacement labels for these batteries that are simple to place on the batteries to allow them to travel internationally. I believe new certifications are online now.