Hi
If you just want to retexture the games models.
You need a program that De-PBO's, PBO files. (there are some in the editing section of this site)
In my computer go to
c:/program files/codemasters/OperationFlashpoint/DTA
In there you will find PBO files. Copy Data.pbo and Data3D.pbo to somewhere on your computer.
Use the De-PBO tool to unpack it to a place where you will be making your addons.
You can delete the pbo files you copied.
In Data.pbo that is all the game textures. (paa & pac)
In Data3D.pbo that is all the game models (p3d)
Hope this helps you.