How to put a picture in background and stretch it (off 2003+2007)?

[msoff20xx]

Assume I have a *.png or *.jpg picture of size 300*200 pixel.

I want to

- put it into an existing word doc on ONE certain page (not all)

- put it in background so that all other stuff (especially the actual text) is on top

- stretch it to 600 *250 pixel

- and position it to (10,40) = 10 pixels from the top border and 40 pixels from the left border.

How exactly can I do it in

- Office 2004

- Office 2007

?

Matt