Firstly, thanks for the great hack.
If I am doing something wrong, please tell me, but I have tried several different ways to change the streaks with the same result. No matter what I do, the only way it saves the streaks is with the correct number of kills. It is nice that it treats them as the support streak so I can die and still earn them, but they all still require the original number of kills. If that is the intent, then I misread the original post. However, the way I read it was you could for instance have a Pavelow as a 4 kill streak. I have been unable to get it to do that. If I choose the streak while I have the menu open, it does show the low kill number with the chosen streak icon, but as soon as I click anything or escape out, it reverts to the original streak.
Edit: I have tried both closing the program before leaving the streak selection screen and leaving it open, neither works.