You need to set it as Faraway place. Then fill the 46h and 47h offsets with information from the following list : http://projectpokemon.org/forums/showthread.php?5532-List-of-46h-and-47h-values-of-HG-SS-locations
The reason for that is because Shininess is partially determined by your SID, and since the combination above does not exist, the Pokemon will be hacked. Maybe I could then make changes to IVs ?