If you're coming from the southwest on the A4 this one works:

http://maps.google.com/maps?f=q&sour...58859,4.689134

If you're to the east of the airport then this one may be good:

http://maps.google.com/maps?f=q&sour...37398,4.817977

I think I've been to the second one before - had to refresh my memory on Google Maps.