Interesting to discover that the more recent Pa500 does not recognize SDHC cards, which are essentially higher (over 2 Gb) capacity SD cards, yet
My Korg microARRANGER is essentially a Pa50,
which is a generation older than the Pa500, yet recognizes the higher capacity SDHC card.
My Sandisk brand 8 GB SDHC Card works great with my Korg microARRANGER
so I would have expected it would work on the Pa500 as well.
I was advised that formatting the SD/SDHC card on the keyboard itself critically important.
I was also recommended to purchase Sandisk to assure compatability.

Scott