Thanks Pawan. Getting BGA pins coordinate seem simple but the possition of decoupling caps are always different the BGA pins.
Also, if we have more than 1 Power Net (more than 1 decoupling cluster/group) then that is impossible to place exactly to its relative Power net.
I would prefer "Sequent placement" in PADS that i just simply select goup of decoupling, point the cursor to BGA area, then the decoupling which i selected will snap automaticly to my cursor. I dont need to select 1 decoupling, place to BGA then go back to select an other one, place to BGA then go back... and so on :(.