Originally Posted by BonezMcCoy
For you to record the output of your soundcard you must send it back in through an input, or in simpler terms, Reason or any other DAW cannot record what goes OUT but what what comes IN... Two ways to do it:
A real cable
Virtual cables using JackAudio or Soundflower
This is what is done by everyone on every other DAW that I personally know.
As Bonez says above Jackaudio works very well, I have used it for the exact purposes that you want to do in the previous thread. There are also detailed instructions on the Jackaudio website.