Open up PPF-O-matic. At "File to Patch", click browse and check "all file types" and locate the map cache file that you are patching; say you want homing rockets on battle creek: ftp over the cache file of battle creek, and select that file as "File to Patch". Then, where it says "Patch To Use", Select the homing rocket patch for battle creek. Click Patch, and you're done.