Watermark in Word Mac 2008

I'm having the hardest time figuring out how to get a PRINTABLE watermark or background in Word for Mac. I can get the watermark but can't scale it to fit. The size is 8.5 x 11 so I need the whole page. I was able to get it too look right with the background image, but that won't print.

I also need it for Excel but can handle that later.

any help is much appreciated.

thanks.
Justin