Hey guys, thank you both for taking the time to look at my problem.
Vinesh, I need the transparency, what I needed is to keep while also keeping an alpha channel to prevent seeing the layer in its entirety, not get rid of the multiply blending mode.
Cassius, if I turn off the collapse transformations switch I lose the relative position I need, here’s what I did in the end and solved my problem:
I turned off collapse transformations in the layer and set the blending mode to multiply, went inside the comp and set them to multiply too, sort of a double multiply thing, then I turned the collapse switch on again, so I recovered the 3d position, immediately the blending mode changed from multiply to – (you know, when you can;t change it without uncollapsing) but nonetheless the blending mode worked as I needed.
Thanks again!