OK, that didn't take as long as I thought it would.
First, I'm assuming that you aren't really familiar with what the content of the SysEx message that is needed to program the Breath Controller. Page 18 of the manual that I downloaded gives the basic details that I think you need.
The basic format of the SysEx string is "F0 00 00 50 17 01 aa bb cc dd ee F7". The parameters that you can specify are aa, bb, cc, dd, and ee. There is actually more that you can do (pages 14-21), but this is that basic command that I think you want.
Assuming that you want the Breath Controller to send ModWheel (CC01) on Channel 1 and have the data range from 0 to 127, the parameters you need to send are:
aa = 00 (send CC data)So the entire SysEx string you need to send will be "F0 00 00 50 17 01 00 01 01 00 7F F7". If you want to send different a controller, change parameter bb according to the table on pages 24-26 of the manual. If you want to send on a different channel, change parameter cc according to the table on page 23 of the manual. If you want to change the min/max range of data sent, change parameters ee and/or ff according to the table on page 27 of the manual.
bb = 01 (controller 1 = ModWheel)
cc = 01 (channel 1)
dd = 00 (minimum value sent will be 0)
ff = 7f (maximum value sent will be 127)
Here's how to send this data using MIDI-OX (I am assuming that you have successfully MIDI-OX configured to send data to the Breath Controller unit):
1) Select the menu item View -> SysEx
2) Enter the SysEx string in the SysEx Command Window
3) Select the menu item Command Window -> Send SysEx
4) Ta da! You can see in the "Monitor - Output" window that the data was sent correctly.
I hope this helps! If it does, please click on the little icon of the silver scales in the upper-right corner of my message (just to the right of the text "#3") to boost my lowly reputation on this forum.