I read in the sansa forum about the compatibility with a micro sd hc 8GB memory. The answer was, use the rockbox firmware. I do that, and effectively, it recognize the 8gb memory, but i can write in it trough the player, because when i connect to the usb port, the system reboot and loads the original firmware, which didn't work with those memories.
Somebody now a way to solve this issue with the player. I now that the solution could be buy a micro SD HC card reader, but i want to be sure that there in no possibility with the player.
Thanks