How control opacity of border and fill separately?

I made a rectangle with a border ( I think it's the Stroke in Inkscape) and a fill color. In Fill and Stroke Dialog, when I change Fill or Stroke Paint opacity they both seem to do the same thing. They both affect the fill and the border opacity at the same time. How can I control them separately?

The Alpha channel (The "A" slider in the colour pane for each of fill and stroke) is what you want.

Hi Slow Dog.

That seemed to do it. Thanks.