LG Venus VX-8800

Well I must be doing something wrong. I have installed a 4gig mini and the phone reads it fine. I've transferred pictures and video from the phone to the card. Everything works fine. When I pull the mini and insert it into an external reader nothing shows. No pictures, no video, no folders, nothing. BITPIM shows there is something on the card in the phone but with 0 bytes. Help.

Thanks.