Not quite, the player software only knows how to mount and use 2 disks, you need to find a way to fool it. I've done so by making a RAID array out of the four disks so the player sees them as one big disk, this however requires a custom kernel be built with the raid 0.90 drivers patched in.

Also I tried the adapters you linked too, but couldn't get them to work with 2 cards installed. in the end I ordered 2 off http://linitx.com/viewproduct.php?prodid=11631 and have further modified them to support four CF cards in a MK2a player.