Hello, I don't know if this is of any use to anybody but I've decided to post instructions on how to use Eigenharps with reason 4.
1 load reason and create a combinator with any instrument you want in it.
2 In the options menu open additional remote overrides.
3 Scroll down and find Breath and where it says control it should say breath click to edit this control.
4 Tick learn from control surface input and blow into your instrument - this should then show cc 17, click ok and close the menu.
5 On the combinator open the key mapping by clicking on show programmer.
6 On the right you will see modulation routing and where it says source you can change any of the rotaries or buttons to breath controller in the drop down menu.
7 Then you can change the associated target to anything you want to control with your breath - I normally start with master volume, you can change the max or min levels according to the instrument you've chosen.
If the combinator instrument includes many different synths or effects then normally there is a mixer where you can control the volume.
The above is something I discovered yesterday and maybe there are different ways of achieving a similar result. It works for me and I hope it works for you.
I have to say using a wind controller for some of the synths available in reason is tremendous fun - try low brass for starters.
All the best
Mat