Windows 7 does not natively support USB 3.0 and as such you can try two things. Set the USB Controller to USB 2.0 in the Virtual Machine's Settings and if that doesn't allow it to connect then you need to buffer the connection using a USB 2.0 Hub connected to the Host and the device plugged into the Hub. (I know, neither sounds palatable when one wants to us it as a USB 3.0 device! )
The other option is the setup the USB Drive as a VMware Shared Folder or an OS X Share and access it that way.
BTW Windows 8 natively supports USB 3.0.