If that's even possible it would be like cracking the encryption used for the .fhm, and I personally don't think that's ok. Ask your local computer wizzkid and they might be able to help you rofl.
I don't know why would delete a small small file as the .map, and for your CPU non the less lol.
I'm not sure if it works copying another .map file and just renaming it to the name the old one you deleted used to have. So try that first.
If that doesn't work I'd just drop the whole idea of editing that map. The only way would be cracking the encryption on the .fhm file, and just a few know how to do this, and it shouldn't be done at all.