How to get glitched AC2 Brotherhood Trophy?

Hi there,

I've finished AC2 Brotherhood yesterday and got almost every trophy I wanted.
There is one small problem with the trophy for DNA sequence 3 though.
It did not unlock. As I said, I've finished the whole game now and everything else unlocked just fine.

Can anybody here help me in fixing the trophy file so I can get what I earned?
I did some googleing but couldn't find any tutorials or explanations regarding this matter.

Thanks in advance
orangensaft


PS: I know there are things like Instant Platinum. I don't want that. I just want my earned trophies. I also tried using Neo Angelus Trophy Editor. The applications hangs at startup.