Instructions
Open BrawlBox, an application included with Brawl, then click on the "Plus" icon to expand "sc_selcharacter_en.pac." Click on the "Plus" icon below that and select "char_bust_tex_iz77."
Choose a CSP among the list to edit and begin to modify the parameters listed under the "Texture" panel to begin creating your CSP.
Change the width, height and format to create your CSP, but ensure that you don't exceed a size of 128 x 160 pixels.
Open the modified CSP file in an image editing program if you want to make further changes to your CSP's design. Save the modified file in the same location in which the original was stored.