Arghhh>Can't print off homework with coloured background! Word 11 on Mac

[Ingles2]

If anyone can help, would be so appreciated.
Ds1 has created a poster in Word 11 (student version) on mac. It has a coloured background he created in layout> pagebackground> colour
However when he goes to print, the background is white.
Why is this? and how do I solve please

Found it!
Juswt incase anyone wants to know... you go to the print window, choose microsoft word in drop down box, then word options and then click option for print background colour and photos.
Phew!