Hi, I know this post is well old, but you may still want the answer or found out yourself.
If using the auto setting - you cannot adjust it to the windows, only the feet or the front vents, if you want windows you will have to use the manual setting.
I find the auto setting is great if it's cold as the vents will only blow when the engine is warm enough for warm air.
If you want to demist the windows, press the front window demist and it will put on the A/C which works a treat,
Hope this helps
wirralot, November 2008