Wow, AGJM! You have done some seriously remarkable work! I truly admire your imagination (something I seem to be lacking). The orange glow art is among my favorite. Just a very cool effect you've achieved with those.
Look, I know I'm REALLY late in responding to the question of how to do the crescent on the helio sig, and chances are, you've already figured it out. However, on the off chance that you haven't, I hope I'm not overstepping my bounds by offering the easiest method I've found for creating it.
First, using the line tool, draw from top to bottom and give it a nice curve.
http://i218.photobucket.com/albums/cc182/1stBass/stepone.png
Next, gaussian blur it at about 10-13
http://i218.photobucket.com/albums/cc182/1stBass/steptwo.png
Finally, draw a transparent linear reflected gradient. Easy as pie.
http://i218.photobucket.com/albums/cc182/1stBass/stepthree.png
Not sure if you actually needed that information, but I thought I'd offer it anyway. I look forward to seeing more from you.