I'm having the same issue of my hacked 3760 not recognizing my new voices. I have generated the proper "all files" unl via the beautiful screen shot instruction on here, but nothing new shows up. The checker also verifies it's unlocked and good to go.
Perhaps the new 4.90 firmware I have denies it? Or perhaps I'm inputting the wrong unit id. Unit id = S/N, correct? My id only has 9 digits.