Have you seen this
, and this
You're off the mark in that re-amping typically
doesn't involve first processing a signal using an amp simulator (in your case, Guitar
Rig) and then feeding the processed signal into a real amp.
The essence of
re-amping is simply to record the unprocessed DI'd guitar sound (typically alongside a
mic'd cabinet), so that later you can do what you like with it.
If your friend
uses the XT Pro when he plays live, then I would suggest that he use that when you record
together. I note it has a connection labeled "unprocessed guitar out" on the back of it.
Feed that into a line level input (not the instrument input) of your Motu and record it,
on a separate track to the processed signal from the main outs of the Pod. (There's some
helpful words in the Pod manual about this.)
Then if you later decide you're
unhappy with the processed Pod signal, you also have the unprocessed signal, which you
could process using Guitar Rig (or the Pod on another setting, or the Peavey head + a cab
+ a microphone).
Hope this isn't too unclear,