You can create your own BattleZone maps in a paint program that supports editing Bitmpaps, like Microsoft Paint.
Flags must be 64 width x 32 height pixels.
The flags can only be drawn using two colors, true black and true white. (For white - RGB is 255,255,255 and black - RGB is 0,0,0).
File Name and directory:
The file name starts "flag" plus a four digit number of your choice. The flags can be saved as "flag0037.bmp" to "flag9999.bmp". Place the flag inside the "addon" folder at the root of the Battlezone directory. Now, it will appear when you scroll through the flags.
Giving the flag to others:
The flag will automatically by transferred to the other players when you play multiplayer.