Well, i'll make some instructions:
1. Make a security copy of korea 85 folder and rename it Korea 50. (just keep an unmoded one just for security reasons)
2 Download TPO (Third Phase Offensive)
2.1 Unzip it into the Korea 50 folder (the one that you don't want to keep unmoded)
3.Go to
www.volcanomods.com and downloads any PZC pack containing the american-ab folder, (for instance, Bulge 44, Normandy 44 or Market 44 should work, althought i suppose that there are others).
3.1 Unzip the pack anywhere in you hard disk and open the american-ab folder
3.2 Copy Unitbox.bmp (from the Volcanoman pack) into the korea 50 american-ab folder (it should not overwrite anything if it does, just tell windows to overwrite)
4.0 Open the game and enjoy, i'm working for a fixed version right now and it should not be very late...
EDIT: Oops, forgive my clumsiness but i forgot to include the .pdt file into the package...