Actually, probably the best way to do this is to disable the boot configuration for this card and just do it from KDE each time. The other way to do this would be to write a script that lets you choose which network to access and have that run at boot time. If you are feeling extremely adventerous, I've posted a perl script
I use to scan for access points and then let me choose. I run it at boot time. I haven't tested it much, so it may not work for you.