It's been very frustrating.
I own 2 SP808. One upgraded to EX the other one "virgin".
None of them works with either a HD of a CF Reader.
With the HD I had better results. I found in a store nearby a drawer for 2,5" HDs that changes the socket to standard IDE and it fits in the 2.5" bay of the SP. Plus.. you can extract it and connect it direcly via USB to a computer. To make it work in the SP I had to connect it to an external power source because the SP only provides 6V. The experiment started well: i could format the HD (20GB) but then it wouldn't sample or play the samples. It hangs. I'll try with a smaller HD but it's hard to find.
I've ordered a simple CF reader from E-bay. 99cents...
Now I got my paycheck so i'll order the one from amazon...
Any suggestions? The HD has been the most successful for now...