If you want to add custom objective sprites to your map, you can choose one of custom 1, 2 or 3 from the drop down in dod_control_point entities. Then put the files in a dir like this, named with the same name as your bsp file.

icon_obj_custom1_allies
icon_obj_custom1_axis
icon_obj_custom1_neutral
icon_obj_custom2_allies
etc...