So anyone have any idea how to convert psychihc powers from the other games to BC ?

Well, Rogue Trader rules and Black Crusade rules for psykers are already very similar. A little while ago i found www.myth-weavers.com/showthread.php which is someone's unofficial attempt at converting the Dark Heresy powers to Rogue Trader powers. All you need to do is change the discipline basic technique into a technique that you have to buy like the rest of the powers and have it be a prerequisite for the rest of the disciplines techniques.