I finally managed to use my 3 in 1 usb card reader. A little background info: I was able to use it in SuSE 8.2. Just use
However, when I switched to RH9, I could only mount the /dev/sda1 (the compact flash). I have fiddled around with it for one month. Fortunately, I got the trick from this page, http://linux-sxs.org/hardware/flashreaders.html
The trick is just to echo something to /proc/scsi/scsi. Take a look at it if you are struggling with your multi-card flash reader.