I'm pretty sure the issue is this: the security helmet and katana were designed to unlock with the original 49 (it is 49, right? please correct me if I'm wrong) achievements and 1000 GS. So, whenyou reach to 1000 GS using some of the new achievements, the armor may be temporarily unlocked, then relocked. Mine did this for a few months after I hit the 1000 mark. I think I had all but three of the original achievements. So I decided randomly to play a campaign level i hadnt got the achievement on for scoring so many points. And when I did and got the achievement, the armor was permanently unlocked. My brother, on the other hand, doesnt have very many of the original campaign achievements. So my advice: get as many of the original achievements as possible.