Best to copy an existing CMT file, any one will do, to the slot your renamed scenario is at. Then open the scenario in the editor and re-save to a new slot, now renaming the scenario to the correct name you desire. If you need to extract several campaign scenarios, recycle the one renamed slot with the copied CMT file.
The CMT file is NOT text - it is binary with a string at the front, usually edits with <= the number of characters in the former CMT will work (but not alwayys). An edit that adds a longer string than the original had, is more prone to error. It's a C string, so expexts a null terminator (hex 0), and overwriting that can crash. As can editing with non USA-ASCII (Spanish text, say a cidilla will work OK on the Spanish guy's PC, but cause random crashes on UK, USA, and possibly other versions)
I'd edit one with a hex editor myself, ensuring a zero (0x0) at the end of the char string. Not sure if it excpects a CR/LF there either (Inspecting in a hex editor will show - 0x0D 0xOA AFAIR)
I have a very old (but it works
version of frhed go to :
http://www.kibria.de/frhed.html for the latest - a nice simple to use hex editor. HINT - put a shortcut on the desktop, and you can drop any file you want to hex-examine or edit onto the desktop shortcut icon and frhed will open with it
Just dumped a CMT frtom scenarios into frhed.exe - the string ends with CR/LF/NULL ie 0x0D 0x0A then 0x00-> EOF
So- a quick edit and save from frhed (and not textpad) will do the trick without any re-save needed.
Cheers
Andy