Changing [entire] background of a GtkTextView

[Vadim Berezniker <vadim berezniker com>]

I want to change the entire background of a GtkTextView to the 
background of its parent container. Using Tags, I can only change the 
background of the parts of the view with text.
Changing the background using the widget style has no effect. (The only 
thing that seems possible to change is the text color).

(Basically, I'm trying to have a fancier label using a GtkTextView)