I can't get this to work on a HX Stomp then, since I can't switch input and outputs as freely as on the bigger units?
I've gotten closer by setting path B to Send as you wrote and then connecting a physical patch cable from Send to Return L plus setting a Return block on path A, or connect the cable to Input R with the risk of feedback (using a Y-splitter down to path B for separation.
USB interface is then set to input 3 and out 3 (mono is fine for me). Using the send/return with a cable gives me a dry signal as an extra and I can't seem to find how to remove it from the equation.
Is this a doomed project and the answer is "get an LT again" or is there something to be done?