Exporting a png sequence for further compositing

Hi,

I’d like to know whether it’s possible to export a png sequence of a screen space GPU particle fire system for further compositing.

Can baking the animation and using a white texture and black background be a way to acquire an alpha matte to make image sequence compositable?

Or is there a way to export a png (RGB + alpha) sequence out of cinematics, matinee or the sequencer?

I need this so bad, please help!

I was hunting around for a way to get alphas to work as well (with exrs mind you)… This would be extremely useful, right now we have little options if we want to enhance our sequence outputs with effects or whatnot outside UE.