BB help says:
Click on Options, then Device > storage.
Hit the key and tap/click Enable USB Mass Storage.
Nex time you connect to your computer, you'll see two external 'drives' - your phone's internal memory and the smart card.
I didn't see anything that says Enable Mass Storage. But when I plugged the phone into the computer I did see the option for "Sync Media". Using that I then saw the Smart Card. In Options I do have checked off Media Card Support.