I mean the Alpha Mask plugin thing...
http://www.getpaint.net/users/Illnab102 ... haMask.dll
EDIT: Oh, I never looked at the bottom of that post, BoltBait. XD
You can create a white to transparent gradient and give it a higher z-index than the text and backdrop color. That would make it look sort of like my signature but it would be in a cell with a solid backdrop.