problems while gsc modding

for some reason when i try to add a GSCfile to my common_level_temp_mp.ff it disappears and deletes what I've written on HXD.
Does anybody know what I am doing wrong ? BTW i am new and i am trying to make a mod menu for cod modern warfare reflex (MWR).   

i figured it out already...

Maybe tell us the solution still

Bully@WiiPlaza wrote:Maybe tell us the solution still

i went to ff viewer 2.65 and opened a .ff file with ff viewer 2.65 when you open a .ff file it makes a new .dat file in the same folder that you got the .ff file that you wanted to edit then i went to hxd and i opened the .dat that ff viewer generated and changed some of the names. then i saved it on hxd and went to the ff viewer and pressed extracted .ff and i chose the one that i had just changed and that was all

hope you guys understand it sounds kind of hard but it's not if you guys want to edit a .gsc file just ask me or skype me