[Help] .OZT invisible background?

Hi all! I need edit loading text. I convert from lorencia.OZT file to lorencia.TGA with photoshop and save it. Then i convert back. In game i dont see invisible background. What need do to create invisible background?
Original background is black color. I put black color - but in game - i see black, not invisible

upppppp

TGA's have alpha layers. Those are used for transparency.