My scripting abilities are null.
That can make things difficult. Try to learn scripting, it's fun and not as hard as hard as you may think!
Anyway, this should work without any external scripting if you add it to each units initialization:
Code:
this addEventHandler ["killed",{hint format ["%1 killed by %2",_this select 0, _this select 1]}]
EDIT: oh wait you said you needed it in MP. Getting the message to transmit over multiplayer is a different matter, but I'm sure it's possible. It'll run on the same basic principle of using "killed" eventhandlers.