Look for the text/background tab in the media management pane... you may have to scroll left or right to see it... if it isn't there, you may have to also use View>Text Background from the pulldown menu (Do it twice and it will come to the foreground).
I've got the Text/Backgrounds media management window up. The only selections I see are Color Gradient, Credit Roll, Solid Color, Test Pattern, Text, and two legacy plugins. I tried dragging the Transparent Text item over an image, but it blocked out the underlying image. There is no "Surface Generator" option ... ?