Downloa Winrar. Make a new rar file called z_background.rar. Make a new folder in it called "images". Now, if you already have or need to make a background,place the menu_sp_image.iwi file into the images folder. Exit out and rename z_background.rar to z_background.IWD. Put the file in your m2demo folder. Done.
TuT for making custom Backgrounds: Sry, cant fin one. See if you can use this, its my old tut. Steps are similar, but its for Callsigns instead. View topic - [TUT] Custom Callsigns - fourDeltaOne