As you said, hardware is emulated, there's no real Renesas USB controller, so you can't update the firmware, as a firmware is no-volatile code that resides on the actual chip, and the actual chip is Intel.
However, it's probably possible to fake the firmware version if you find it where it's stored, maybe in the registry?
Additionally I would suggest you would contact their support and ask them if they can do anything about it (which they can, they just need to update their code not to check for firmware if it's running in a VM).
Last edited: Aug 16, 2014