I have searched for this but somehow can’t find an answer.
I can set the pgm source and pgm destination for a modulator via the front panel. But can I do this through the software editor?
If I can, I am clearly asking the wrong question or asking it the wrong way. If I can’t, it seems strange, as that has to be a really useful creative device.
Assuming you are referring to the Sub 37 editor: the PGM SRC and PGM DEST settings are in the extended parameters section of the editor. You can see them in on page 2 of the Sub 37 editor manual. As explained to page you can click the the grey triangle at the bottom to show/hide the extended parameters window.