A USB Instr is one that is compliant with the USBTMC (Test & Measurement) class. Vendors such as Agilent, Tektronix, etc. use USBTMC since you can use the same commands as the instrument with a GPIB or Ethernet interface. Unless the vendor says so, it's unlikely that your device is using this.
You will probably need to create your onw USB RAW driver. I would strongly suggest reading the series of nuggets by Intaris.
