Regarding the LDK EMS over virtual server, the requirement is that the Master key should be detected as local in localhost:1947/_int_/devices.html on that machine, be it a virtual machine or physical machine.
ISVs can connect their Master key to an over-the-network USB solution and access it from any physical or virtual-machine as if it was connected locally.
We recommend myUTN-80 by SEH Technology. This device was tested thoroughly with various SafeNet protection keys and is backed by partnership between SEH Technology and SafeNet.