Help on editing the default reticle on holosight?

this isnt really a hack, i was just wondering how i could change the reticle file and not have the game say "invalid game data" after. just curious.
I unzipped the Weapons_client file and changed the Holo_red01 to have a Trijicon sight shape, and kept the background the same color and the file the same width and height. I rezipped the file and put it back in its place, but it still tells me invalid game data! could someone please help me, i have no idea how that particular game works or what to do to fix this.

You just cannot change the game data/files of Battlefield Play4free, once you enter a game the client checks to make sure all the data matches their expectations or you get kicked with "Invalid game data". End of.

But check out this unlimited view distance glitch I managed to figure out!