battle backgrounds

As far as i know, somewhere in the rom, backgrounds are loaded and identified with a byte...

Could someone tell me where i can find the hex code that loads battle background images inside the game, please?

What i want to do is to replace some background with another one already present inside the game: i don't care much to have redundant backgrounds, for what i'm planning to do.


There's also another question: if i do that with scrolling backgrounds, like the mine cart/waterfall backgrounds, will they scroll even in the new position, or the scroll feature is bounded to the original position slot?