Here is the location of the ASPI drivers that are needed for the USB drive to be supported under Micrsotudio.
Download this file:
http://www.mtu.com/upgrades/microstu...idrivers16.exe
You will need your Microstudio Email and serial number to install this program.
Then go into Microstudio, click on the Drives menu at the top. Click on ASPI drivers. Make sure this is set to USE the MTU Installed Driver. Then close Microstudio and Reopen it. This will then fix your problem.