ITMS 8.6 RU2
"Asset types" are retreived from "Resource type" table:
Resource types are defined during the "Basic inventory". You can find it under Resource Manager> Inventory> Basic Inventory >>AeX AC Resource Inventory Summary.
Currently, ITMS detects VMware, VirtualPC, and Nutanix as Virtual Machines. Other Virtual machines are not detected yet and probably will be in the near future.