Why an external disk drive is NOT seen in the W7 host machine, however you can see it in the XP guest machine

Hello,

This is a strange situation and is happening to me with a new Toshiba 500GB Canvio® Slim Portable Hard Drive.

1. If I install the drive in a W7 machine, without VMWare Workstation 9.02, the disk is automatically detected with no problems.
2. If I install the drive in a W7 machine, with VMWare Workstation 9.02, the system try to find a driver and finally it says that could not find it. Please see image "01" that shows the status in the W7 Device Manager. The drive is there in "Other devices/External USB 3.0" but flagged with this yellow sign: !  
3.   BUT here is the most strange thing. In the situation detailed in (2) above, if I start a Windows XP guest machine, I can see the "Toshiba external DriveUSB 3.0" drive and connect it to the guest machine!! Please see image "02" and see this drive in the XP Device Manager .

Appreciate a hint.

Thanks a lot