I have a theme which sets the background of my panel to a certain color, even when I tell it to be transparent via the panel properties.

In the theme's gtkrc file, what do I need to change to set the background color to be trasparent? I haven't written my own themes before, so I'm kind of lost. Another theme I have does it right, but since I don't know how to read the theme file, I don't know where to start.