I have the NeoSD Pro and I have downloaded the cheats file you reference here and placed the ".dat" files into the root folder of the SD card, at the same place as the ".neo" games. Then, I have tested in game cheats and for each game, it says "No cheat available". Is there anything else to do to activate the cheats?
My firmware: NeoSD Pro firmware 1.07 R08.
Thanks for your help!