After reset 0 score , delete previously unlocked resetted achievements

I completed 90% halo 3 achieve. halves (45%) with horizon and half alone (45%).
The reset arrived.
I can unlock the remaining 10% but the 90% of first are blocked and “unobtainable”.
So I opened my profile resetted with horizon, I deleted the achievements unobtainable and I re-unlocked them(all 90% achieve.). I have put the profile in the xbox 360 the problem seems solved, … BUT !!! As soon as I synchronized xbox live, he deleted everything. Other ideas for delete achievement locked on xbox live ?

It isn’t possible to earn or unlock achievements that have been reset no matter what you do.

It s sad