creating particle sprites

i'm attempting to create a few particle sprites in photoshop and wondering what's the best way to go about it. i noticed that the "lens flare" filter creates a very nice effect that could be used as a particle, but i'm confused as to how to handle the background (alpha channel)? when i load the sprite in blitz3d, of course the background shows too and it looks silly.

anyone have knowledge on how to keep the background transparent? photoshop won't let me run a filter on a transparent background (says the selection is empty).

thanks

For a lens flare, render the flare on a black background and set the sprite to 'add' blend mode in Blitz. Come to think of it, isn't 'add' the default blending when you LoadSprite?

More generally, you can run the filter normally and then copy/paste the image to the alpha channel.