Hi, I don't know if you already resolved this issue, but I just got the same thing when I upgraded yesterday, Nov-3-2009, from VirtualBox 2.2.4 to VirtualBox 3.0.10. I mean, my CAC reader was working in the previous version, and now it was not working even the VirtualBox was recognizing two (2) CAC readers. I was playing around with this issue until I got it resolved.
Just for clarifying, I know it is a Linux issue's forum, but maybe this fixing can help. Therefore, I have Windows Vista, and I use VirtualBox to run Windows 2000 (where the CAC reader was working on the v.2.2.4 and not in v.3.0.10). In the steps below, I will call "VOS" (for "virtual operating system") as the operating system having trouble with. In my case it was Windows 2000.
To resolve it:
1. Unplugged the CAC reader.
2. Go to the Settings of your VOS that is giving you the issue in VirtualBox.
Note: To go to the Settings that is located on the Sun VirtualBox console, make sure you have closed the VOS in VirtualBox you're using, so it can be manipulated. Otherwise, the Settings button will be disabled.
3. Click on the USB tab at the left panel.
4. Remove the "ActivCard USB Reader V2 " device filter from the list.
Note: The name could change depending of your CAC reader.
5. Start up the VOS again.
6. Reinstall the CAC reader drivers from "Add/Remove Programs" of the "Control Panel", from within the VOS.
Note: In my case, I have "ActivClient for CAC - PKI Only" and "ActivIdentity Device Installer". Probably, it will prompt you to restart the VOS, if so, restart it.
8. On the VOS's menu, go to "USB Devices" under Devices, and click the CAC reader device you want the system to recognize.
Note: You also can right-click on the USB icon*, and click your CAC reader device.
* This icon is located at the "border" of the right-bottom side of your VOS, and not at the left side of the VOS's clock.
9. The system should recognize the CAC reader installing the drivers again, as the first time.
10. Voila! You should have running the CAC reader now!
With all these steps you should run the VOS with the CAC reader supported. I just did the next "optional" part just to make sure the CAC reader will be attached every time I go into the VOS. I mean, it's not necessary because I saw the CAC reader running on the VOS without this "optional" part, but just wanted to make sure, before something else happens and then you don't remember how to fix this issue.
12. Go to the Settings of your VOS.
13. Go to the USB tab on the left panel.
14. Add the CAC reader device to the list.
That's it! Hope this helps.