It works fine for me. Did you do the whole "giggledisk" thing to make the mountlist as per the instructions? Also, do you have a card that is considered compatible (there's some kind of program that gives you all the specs of the card when you run it, it is included in the saga drivers)?
I don't use it for this purpose though. Instead, I use it for networking, via a SDNET adapter. Much better usage of the slot, seeing it's worthless for transfers in the fashion of the PCMCIA slot / CF adapter of an A1200 or the ACA500+.