How do you save luigi?

in Super Mario on nintendo ds. How do you save luigi. i've completed the game twice without him an it's driving me nuts!!!!How do you save luigi?
you dontHow do you save luigi?
In the game there will be a level which you can find by chasing the big boo in that room with the red carpet and it will lead you to the door and there will be a bunch of boos and a cage you have to get near the cage so it sucks you in to the haunted house level and in that level you have to go through all these stupid stunts to get to get to the room with the painting of i think Mario or someone and then it changes to luigi's painting and you jump in then it lets u battle big boo, once done he will give you the key to unlock luigi's doorHow do you save luigi?
Stars needed - 8

Characters needed - Mario

Location - Big Boo Battle, inside Big Boo's Haunt from course 2 onward. Head

into the mansion, up the stairs and into the right most room. Head

into the corner and hit the ? block for a power flower. Rise up and

land on the ledge above (press R to land) then head through the

door. Jump through the Luigi painting.





This is a maze like area where you have to go from room to room to find

the boss. Use the magic of stereo sound to follow the laught to indicate where

to go next. If you take the wrong door or fall into the black abyss, then you

start from the beginning.

Basically the route is like this; take the right door, then to the centre

and left over the collapsing bridges and through the door. Jump into the

center platform, then right and through the door. The next door is the left

one so to make this room easier long jump straight to it. In the final area,

sprint over the collapsing bridge then take the platforms up to the boss.

You will see a mirror in front of you. Wait a while then approach the

mirror to make the Big Boo appear. He is invisible due to the mirror however

you can see his reflection, so use that to attack him from behind or the

sides. You can still see his shadow so use that to know his whereabouts.

And remember you are using the mirror to show his direction and that you

have to sorta work in reverse. When he teleports, he will come to the other

side. So if he was in the mirror he will show up on your side and be invisible

on the mirror. If you touch him then you lose 2 pieces of health, but luckly

there are coins lined up on the sides to help you. Like the other Boo bosses

it takes three hits to take care of him, and then he will give you the Luigi

key.