I think I got it working.here is the sequence:
Power down guest, in VB interface enable USB, no filters. Power up guest.
Guest installs a bunch of drivers. May need to reboot guest here.Don't rush!
host detects new usb device and installs driver for it. Asks to reboot.
Power down guest. Don't check "Revert to snapshot"
reboot host, power up guest
steps above I had to do a couple times.
Insert flash drive
Host detects it
Go to the guest In the status bar click on usb devices, select flash drive.
Host looses it, guest finds it. Guest installs driver for it.
Vu a la