Not worked for me.....
Impossible...What exactly did You do?
I tried it for menu.swf though...
First copied the desired menu.swf in RES folder and simultaneously deleting the existing one.
After that changed screen text language from english to any whatever else option.
Next, went back to menu but it does not changed.
There It is...Try Changing BOTH
the 'Screen Text' language and the 'Input Language'...THEN
go back to the menu and it will be changed