I can't figure out the right settings to shoot exteriors on the EX1. I usually set the white balance switch to "A" (Which gives me 3900 color tempetature). When I switch to "B" I'm also on 3900 color temperature. That works fine for interiors and tungsten lighting. However when I shoot outside I need to switch to "preset" which gives me some variable color temperature (with mediocre color end results). All I want is a two setting switch: Interior and Exterior. What is the way to get that?