You can boot into OSX and select Windows in the Startup Disk control panel, likewise you can go the other way using the Bootcamp Utility which loads in the Windows System Tray.
This does require you to boot into the current OS and restart into the Alternative, but because a boot loader such as REFIT will not support a wireless keyboard its probably as good as it will get.
Boot Picker which I find rather annoying because it needs to load OSX before you can select Windows may actually prove useful to you in this situation to.