Thank Sanguinus for brothers like BW and CI who are our fountains of knowledge. This is a good list. Now I'm thinking of it, I think they have the chapter symbol on the left shoulder pad and their squad number on the right. At least thats how I did mine. The black skull sounds very cool though. I will try to see what I can find when I get access to my own materials as now my interest is very much piqued. Perhaps I can also find a reference to the black skull symbol to support this list.

"Strike First, Strike Hard, NO MERCY!!"