problem to costumize a key

hello! I’m doing my own keymap, and need to change a shortcut for “rip vertex”, that by default is set with “V” key. Everytime I modified it, save the new configuration and re-start again blender, It appears again with old key shorcut. Also I note that happens the same with “loop cut and slide” key. Is like they are unmodifiable key. Somebody knows about this strange problem?

I know this isn’t a very helpful answer, but I can’t replicate this problem at all. I would suggest that you just haven’t clicked the “save user settings” button, but that doesn’t explain why it only applies to those keys,
Sorry not to be more helpful,
C