I think the reason for that is, that you mainly see a sharp ring flashing, and that it's not as solid as the default textures. For me there appear to be several rings sometimes, actually ( I like it =) ). I'm not good at gfx but maybe I can do something with ultrafractals or so, that's a bit more thick. Just need to re-setup my windows as it seems that my kmixer is jammed. and I can't do anything without my music ^^
fading itself is controlled by the engine I would think, nothing to be done there on the texture side. you can just do something more solid