Hi. I'm not sure what a .cda is, but it doesn't show as an option in my version 4.22 (windows 7) either.
But if you are wanting to convert mp3s to burn to a cd-r, then I would choose output format: .wav, Encoder Options: 44100Hz, 16 Bits, Stereo.
Of course, ExpressBurn will automatically convert mp3 files when added to an Audio CD list.
http://www.nch.com.au/switch/kb/1405.html