Brawl Wall messing up

[Yoshi6852]

I make some 2D stages and i've noticed that when I open up one in Brawl wall and then save it, it looses the .pac extention, so I rename it into a .pac extentencion, but when I load it up in brawl the background goes funky. Anyone else have this problem? The only 2D stage i've made that worked perfectly I didn't load in brawl wall.