i have searched the interweb and found this here
and says Tweaking, also known as holepunching to commemorate its discoverer (a GameSpot forums member by the name of "Holepunch"), is a glitch in Diamond, Pearl, Platinum, HeartGold, and SoulSilver Versions that causes the game to fail to load the graphics of an area. Tweaking has not been successfully performed in Generation V
so it may be possible but so far no one has sucsessfully peformed it