How to save png with transparent backround?

I need to capture in editor a .png image with transparent background of the 3D Datasmith imported objects. The best settings i got is to have all black color transparent with the settings on Scene capture 2D - Capture scene - Final color (LDR) in RGB but the picture is too transparent and needs to be placed on black background to be normal. Another setting is to SceneColor (HDR) in RGB, inv Opacity in A but is exactly the opposite of what i need, makes transparent only the background. What am i doing wrong?

No ideeas?